CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-sticky-header-enabled vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>Metallicity - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-sticky-header-enabled vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy", "wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"33ef77ef-98ec-4235-8f1d-45d3b554c54b","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"Metallicity","wgTitle":"Metallicity","wgCurRevisionId":1272295754,"wgRevisionId":1272295754,"wgArticleId":1129919,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["All articles with broken links to citations","Articles with short description","Short description is different from Wikidata","Concepts in astrophysics","Concepts in astronomy","Physical cosmology","Stellar astronomy"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"Metallicity","wgRelevantArticleId":1129919,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove":[], "wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":40000,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q217030","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false,"wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser":false};RLSTATE={ "ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.cite.styles":"ready","ext.math.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","jquery.makeCollapsible.styles":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready","ext.wikimediaBadges":"ready"};RLPAGEMODULES=["ext.cite.ux-enhancements","mediawiki.page.media","ext.scribunto.logs","site","mediawiki.page.ready","jquery.makeCollapsible","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.ReferenceTooltips","ext.gadget.switcher","ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap","ext.popups","ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader", "ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","ext.cx.uls.quick.actions","wikibase.client.vector-2022","ext.checkUser.clientHints","ext.growthExperiments.SuggestedEditSession"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.cite.styles%7Cext.math.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cjquery.makeCollapsible.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.16"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/6/6a/A_Swarm_of_Ancient_Stars_-_GPN-2000-000930.jpg/1200px-A_Swarm_of_Ancient_Stars_-_GPN-2000-000930.jpg"> <meta property="og:image:width" content="1200"> <meta property="og:image:height" content="1259"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/6/6a/A_Swarm_of_Ancient_Stars_-_GPN-2000-000930.jpg/800px-A_Swarm_of_Ancient_Stars_-_GPN-2000-000930.jpg"> <meta property="og:image:width" content="800"> <meta property="og:image:height" content="839"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/6/6a/A_Swarm_of_Ancient_Stars_-_GPN-2000-000930.jpg/640px-A_Swarm_of_Ancient_Stars_-_GPN-2000-000930.jpg"> <meta property="og:image:width" content="640"> <meta property="og:image:height" content="671"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="Metallicity - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikipedia.org/wiki/Metallicity"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=Metallicity&action=edit"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikipedia.org/wiki/Metallicity"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikipedia Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="login.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-Metallicity rootpage-Metallicity skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" title="Main menu" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Main menu</span> </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z"><span>Main page</span></a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia"><span>Contents</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events"><span>Current events</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x"><span>Random article</span></a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works"><span>About Wikipedia</span></a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia"><span>Contact us</span></a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> Contribute </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia"><span>Help</span></a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia"><span>Learn to edit</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors"><span>Community portal</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes to Wikipedia [r]" accesskey="r"><span>Recent changes</span></a></li><li id="n-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_upload_wizard" title="Add images or other media for use on Wikipedia"><span>Upload file</span></a></li><li id="n-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages"><span>Special pages</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <span class="mw-logo-container skin-invert"> <img class="mw-logo-wordmark" alt="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" style="width: 7.5em; height: 1.125em;"> <img class="mw-logo-tagline" alt="The Free Encyclopedia" src="/static/images/mobile/copyright/wikipedia-tagline-en.svg" width="117" height="13" style="width: 7.3125em; height: 0.8125em;"> </span> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikipedia [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia" aria-label="Search Wikipedia" autocapitalize="sentences" title="Search Wikipedia [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Appearance</span> </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en" class=""><span>Donate</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=Metallicity" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=Metallicity" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class=""><span>Log in</span></a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Log in and more options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Personal tools</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="https://donate.wikimedia.org/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en"><span>Donate</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=Metallicity" title="You are encouraged to create an account and log in; however, it is not mandatory"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Create account</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=Metallicity" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Log in</span></a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing"><span>learn more</span></a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y"><span>Contributions</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n"><span>Talk</span></a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Metals_in_early_spectroscopy" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Metals_in_early_spectroscopy"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Metals in early spectroscopy</span> </div> </a> <ul id="toc-Metals_in_early_spectroscopy-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Origin_of_metallic_elements" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Origin_of_metallic_elements"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Origin of metallic elements</span> </div> </a> <ul id="toc-Origin_of_metallic_elements-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Stellar_populations" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Stellar_populations"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Stellar populations</span> </div> </a> <ul id="toc-Stellar_populations-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Common_methods_of_calculation" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Common_methods_of_calculation"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Common methods of calculation</span> </div> </a> <button aria-controls="toc-Common_methods_of_calculation-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Common methods of calculation subsection</span> </button> <ul id="toc-Common_methods_of_calculation-sublist" class="vector-toc-list"> <li id="toc-Mass_fraction" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Mass_fraction"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Mass fraction</span> </div> </a> <ul id="toc-Mass_fraction-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Chemical_abundance_ratios" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Chemical_abundance_ratios"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>Chemical abundance ratios</span> </div> </a> <ul id="toc-Chemical_abundance_ratios-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Photometric_colors" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Photometric_colors"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.3</span> <span>Photometric colors</span> </div> </a> <ul id="toc-Photometric_colors-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Metallicities_in_various_astrophysical_objects" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Metallicities_in_various_astrophysical_objects"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Metallicities in various astrophysical objects</span> </div> </a> <button aria-controls="toc-Metallicities_in_various_astrophysical_objects-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Metallicities in various astrophysical objects subsection</span> </button> <ul id="toc-Metallicities_in_various_astrophysical_objects-sublist" class="vector-toc-list"> <li id="toc-Stars" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Stars"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1</span> <span>Stars</span> </div> </a> <ul id="toc-Stars-sublist" class="vector-toc-list"> <li id="toc-Relationship_between_stellar_metallicity_and_planets" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Relationship_between_stellar_metallicity_and_planets"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1.1</span> <span>Relationship between stellar metallicity and planets</span> </div> </a> <ul id="toc-Relationship_between_stellar_metallicity_and_planets-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-HII_regions" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#HII_regions"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1.2</span> <span><span>H<sup>II</sup> regions</span></span> </div> </a> <ul id="toc-HII_regions-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>Further reading</span> </div> </a> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" title="Table of Contents" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Metallicity</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 51 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-51" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">51 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-af mw-list-item"><a href="https://af.wikipedia.org/wiki/Metaal_(sterrekunde)" title="Metaal (sterrekunde) – Afrikaans" lang="af" hreflang="af" data-title="Metaal (sterrekunde)" data-language-autonym="Afrikaans" data-language-local-name="Afrikaans" class="interlanguage-link-target"><span>Afrikaans</span></a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%85%D8%B9%D8%AF%D9%86%D9%8A%D8%A9_(%D8%B9%D9%84%D9%85_%D8%A7%D9%84%D9%81%D9%84%D9%83)" title="معدنية (علم الفلك) – Arabic" lang="ar" hreflang="ar" data-title="معدنية (علم الفلك)" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ast mw-list-item"><a href="https://ast.wikipedia.org/wiki/Metalicid%C3%A1" title="Metalicidá – Asturian" lang="ast" hreflang="ast" data-title="Metalicidá" data-language-autonym="Asturianu" data-language-local-name="Asturian" class="interlanguage-link-target"><span>Asturianu</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%A7%E0%A6%BE%E0%A6%A4%E0%A6%AC%E0%A6%A4%E0%A6%BE" title="ধাতবতা – Bangla" lang="bn" hreflang="bn" data-title="ধাতবতা" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%9C%D0%B5%D1%82%D0%B0%D0%BB%D0%B8%D1%87%D0%BD%D0%BE%D1%81%D1%82" title="Металичност – Bulgarian" lang="bg" hreflang="bg" data-title="Металичност" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Metalicitet" title="Metalicitet – Bosnian" lang="bs" hreflang="bs" data-title="Metalicitet" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target"><span>Bosanski</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Metal%C2%B7licitat" title="Metal·licitat – Catalan" lang="ca" hreflang="ca" data-title="Metal·licitat" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Metalicita" title="Metalicita – Czech" lang="cs" hreflang="cs" data-title="Metalicita" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Metallicitet_(astrofysik)" title="Metallicitet (astrofysik) – Danish" lang="da" hreflang="da" data-title="Metallicitet (astrofysik)" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Metallizit%C3%A4t" title="Metallizität – German" lang="de" hreflang="de" data-title="Metallizität" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%9C%CE%B5%CF%84%CE%B1%CE%BB%CE%BB%CE%B9%CE%BA%CF%8C%CF%84%CE%B7%CF%84%CE%B1" title="Μεταλλικότητα – Greek" lang="el" hreflang="el" data-title="Μεταλλικότητα" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Metalicidad" title="Metalicidad – Spanish" lang="es" hreflang="es" data-title="Metalicidad" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Kvanto_de_pezaj_elementoj" title="Kvanto de pezaj elementoj – Esperanto" lang="eo" hreflang="eo" data-title="Kvanto de pezaj elementoj" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Metaltasun" title="Metaltasun – Basque" lang="eu" hreflang="eu" data-title="Metaltasun" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%81%D9%84%D8%B2%DB%8C%D9%86%DA%AF%DB%8C" title="فلزینگی – Persian" lang="fa" hreflang="fa" data-title="فلزینگی" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/M%C3%A9tallicit%C3%A9" title="Métallicité – French" lang="fr" hreflang="fr" data-title="Métallicité" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Metalicidade" title="Metalicidade – Galician" lang="gl" hreflang="gl" data-title="Metalicidade" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EA%B8%88%EC%86%8D%ED%95%A8%EB%9F%89" title="금속함량 – Korean" lang="ko" hreflang="ko" data-title="금속함량" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%A7%E0%A4%BE%E0%A4%A4%E0%A5%81%E0%A4%A4%E0%A4%BE" title="धातुता – Hindi" lang="hi" hreflang="hi" data-title="धातुता" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Populacija_I" title="Populacija I – Croatian" lang="hr" hreflang="hr" data-title="Populacija I" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Metalisitas" title="Metalisitas – Indonesian" lang="id" hreflang="id" data-title="Metalisitas" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Metallicit%C3%A0" title="Metallicità – Italian" lang="it" hreflang="it" data-title="Metallicità" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%9E%D7%AA%D7%9B%D7%AA%D7%99%D7%95%D7%AA" title="מתכתיות – Hebrew" lang="he" hreflang="he" data-title="מתכתיות" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-lb mw-list-item"><a href="https://lb.wikipedia.org/wiki/Metallizit%C3%A9it" title="Metallizitéit – Luxembourgish" lang="lb" hreflang="lb" data-title="Metallizitéit" data-language-autonym="Lëtzebuergesch" data-language-local-name="Luxembourgish" class="interlanguage-link-target"><span>Lëtzebuergesch</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%9C%D0%B5%D1%82%D0%B0%D0%BB%D0%B8%D1%87%D0%BD%D0%BE%D1%81%D1%82" title="Металичност – Macedonian" lang="mk" hreflang="mk" data-title="Металичност" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Kelogaman" title="Kelogaman – Malay" lang="ms" hreflang="ms" data-title="Kelogaman" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-my mw-list-item"><a href="https://my.wikipedia.org/wiki/%E1%80%9E%E1%80%90%E1%80%B9%E1%80%90%E1%80%AF%E1%80%80%E1%80%BC%E1%80%BD%E1%80%9A%E1%80%BA%E1%80%9D%E1%80%99%E1%80%BE%E1%80%AF" title="သတ္တုကြွယ်ဝမှု – Burmese" lang="my" hreflang="my" data-title="သတ္တုကြွယ်ဝမှု" data-language-autonym="မြန်မာဘာသာ" data-language-local-name="Burmese" class="interlanguage-link-target"><span>မြန်မာဘာသာ</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Metaal_(astronomie)" title="Metaal (astronomie) – Dutch" lang="nl" hreflang="nl" data-title="Metaal (astronomie)" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E9%87%91%E5%B1%9E%E9%87%8F" title="金属量 – Japanese" lang="ja" hreflang="ja" data-title="金属量" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Metallisitet" title="Metallisitet – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Metallisitet" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Metallisitet" title="Metallisitet – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Metallisitet" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-oc mw-list-item"><a href="https://oc.wikipedia.org/wiki/Metallicitat" title="Metallicitat – Occitan" lang="oc" hreflang="oc" data-title="Metallicitat" data-language-autonym="Occitan" data-language-local-name="Occitan" class="interlanguage-link-target"><span>Occitan</span></a></li><li class="interlanguage-link interwiki-nds mw-list-item"><a href="https://nds.wikipedia.org/wiki/Metallizit%C3%A4t" title="Metallizität – Low German" lang="nds" hreflang="nds" data-title="Metallizität" data-language-autonym="Plattdüütsch" data-language-local-name="Low German" class="interlanguage-link-target"><span>Plattdüütsch</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Metaliczno%C5%9B%C4%87" title="Metaliczność – Polish" lang="pl" hreflang="pl" data-title="Metaliczność" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Metalicidade" title="Metalicidade – Portuguese" lang="pt" hreflang="pt" data-title="Metalicidade" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Metalicitate" title="Metalicitate – Romanian" lang="ro" hreflang="ro" data-title="Metalicitate" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%9C%D0%B5%D1%82%D0%B0%D0%BB%D0%BB%D0%B8%D1%87%D0%BD%D0%BE%D1%81%D1%82%D1%8C" title="Металличность – Russian" lang="ru" hreflang="ru" data-title="Металличность" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Metallicity" title="Metallicity – Simple English" lang="en-simple" hreflang="en-simple" data-title="Metallicity" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Metalicita" title="Metalicita – Slovak" lang="sk" hreflang="sk" data-title="Metalicita" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Kovinskost" title="Kovinskost – Slovenian" lang="sl" hreflang="sl" data-title="Kovinskost" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/Metali%C4%8Dnost" title="Metaličnost – Serbian" lang="sr" hreflang="sr" data-title="Metaličnost" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Populacija_I" title="Populacija I – Serbo-Croatian" lang="sh" hreflang="sh" data-title="Populacija I" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="Serbo-Croatian" class="interlanguage-link-target"><span>Srpskohrvatski / српскохрватски</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/T%C3%A4hden_metallipitoisuus" title="Tähden metallipitoisuus – Finnish" lang="fi" hreflang="fi" data-title="Tähden metallipitoisuus" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Metallicitet" title="Metallicitet – Swedish" lang="sv" hreflang="sv" data-title="Metallicitet" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-kab mw-list-item"><a href="https://kab.wikipedia.org/wiki/Tama%C9%A3uzt" title="Tamaɣuzt – Kabyle" lang="kab" hreflang="kab" data-title="Tamaɣuzt" data-language-autonym="Taqbaylit" data-language-local-name="Kabyle" class="interlanguage-link-target"><span>Taqbaylit</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%84%E0%B8%A7%E0%B8%B2%E0%B8%A1%E0%B9%80%E0%B8%9B%E0%B9%87%E0%B8%99%E0%B9%82%E0%B8%A5%E0%B8%AB%E0%B8%B0_(%E0%B8%94%E0%B8%B2%E0%B8%A3%E0%B8%B2%E0%B8%A8%E0%B8%B2%E0%B8%AA%E0%B8%95%E0%B8%A3%E0%B9%8C)" title="ความเป็นโลหะ (ดาราศาสตร์) – Thai" lang="th" hreflang="th" data-title="ความเป็นโลหะ (ดาราศาสตร์)" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Metallik" title="Metallik – Turkish" lang="tr" hreflang="tr" data-title="Metallik" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%9C%D0%B5%D1%82%D0%B0%D0%BB%D1%96%D1%87%D0%BD%D1%96%D1%81%D1%82%D1%8C" title="Металічність – Ukrainian" lang="uk" hreflang="uk" data-title="Металічність" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/%C4%90%E1%BB%99_kim_lo%E1%BA%A1i" title="Độ kim loại – Vietnamese" lang="vi" hreflang="vi" data-title="Độ kim loại" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/%E9%87%91%E5%B1%AC%E9%87%8F" title="金屬量 – Cantonese" lang="yue" hreflang="yue" data-title="金屬量" data-language-autonym="粵語" data-language-local-name="Cantonese" class="interlanguage-link-target"><span>粵語</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E9%87%91%E5%B1%AC%E9%87%8F" title="金屬量 – Chinese" lang="zh" hreflang="zh" data-title="金屬量" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q217030#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Metallicity" title="View the content page [c]" accesskey="c"><span>Article</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:Metallicity" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t"><span>Talk</span></a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">English</span> </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Metallicity"><span>Read</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Metallicity&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Metallicity&action=history" title="Past revisions of this page [h]" accesskey="h"><span>View history</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">Tools</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/Metallicity"><span>Read</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Metallicity&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Metallicity&action=history"><span>View history</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/Metallicity" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j"><span>What links here</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/Metallicity" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k"><span>Related changes</span></a></li><li id="t-upload" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u"><span>Upload file</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Metallicity&oldid=1272295754" title="Permanent link to this revision of this page"><span>Permanent link</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=Metallicity&action=info" title="More information about this page"><span>Page information</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=Metallicity&id=1272295754&wpFormIdentifier=titleform" title="Information on how to cite this page"><span>Cite this page</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FMetallicity"><span>Get shortened URL</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FMetallicity"><span>Download QR code</span></a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:DownloadAsPdf&page=Metallicity&action=show-download-screen" title="Download this page as a PDF file"><span>Download as PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=Metallicity&printable=yes" title="Printable version of this page [p]" accesskey="p"><span>Printable version</span></a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="wb-otherproject-link wb-otherproject-commons mw-list-item"><a href="https://commons.wikimedia.org/wiki/Category:Population_II_stars" hreflang="en"><span>Wikimedia Commons</span></a></li><li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q217030" title="Structured data on this page hosted by Wikidata [g]" accesskey="g"><span>Wikidata item</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Relative abundance of heavy elements in a star or other astronomical object</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">For metallic and nonmetallic compounds, see <a href="/wiki/Metal" title="Metal">Metal</a> and <a href="/wiki/Nonmetallic_material" title="Nonmetallic material">Nonmetallic material</a>.</div> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:A_Swarm_of_Ancient_Stars_-_GPN-2000-000930.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/6a/A_Swarm_of_Ancient_Stars_-_GPN-2000-000930.jpg/250px-A_Swarm_of_Ancient_Stars_-_GPN-2000-000930.jpg" decoding="async" width="250" height="262" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/6a/A_Swarm_of_Ancient_Stars_-_GPN-2000-000930.jpg/375px-A_Swarm_of_Ancient_Stars_-_GPN-2000-000930.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/6a/A_Swarm_of_Ancient_Stars_-_GPN-2000-000930.jpg/500px-A_Swarm_of_Ancient_Stars_-_GPN-2000-000930.jpg 2x" data-file-width="1777" data-file-height="1864" /></a><figcaption>The <a href="/wiki/Globular_cluster" title="Globular cluster">globular cluster</a> <a href="/wiki/Messier_80" title="Messier 80">M80</a>. Stars in globular clusters are mainly older metal-poor members of <a href="/wiki/Population_II" class="mw-redirect" title="Population II">population II</a>.</figcaption></figure> <p>In <a href="/wiki/Astronomy" title="Astronomy">astronomy</a>, <b>metallicity</b> is the <a href="/wiki/Abundance_of_the_chemical_elements" title="Abundance of the chemical elements">abundance</a> of <a href="/wiki/Chemical_element" title="Chemical element">elements</a> present in an object that are heavier than <a href="/wiki/Hydrogen" title="Hydrogen">hydrogen</a> and <a href="/wiki/Helium" title="Helium">helium</a>. Most of the normal currently detectable (i.e. non-<a href="/wiki/Dark_matter" title="Dark matter">dark</a>) <a href="/wiki/Matter" title="Matter">matter</a> in the universe is either hydrogen or helium, and <a href="/wiki/Astronomer" title="Astronomer">astronomers</a> use the word <i>"metals"</i> as convenient shorthand for <i>"all elements except hydrogen and helium"</i>. This word-use is distinct from the conventional chemical or physical definition of a <a href="/wiki/Metal" title="Metal">metal</a> as an electrically conducting solid. <a href="/wiki/Star" title="Star">Stars</a> and <a href="/wiki/Nebula" title="Nebula">nebulae</a> with relatively high abundances of heavier elements are called "metal-rich" when discussing metallicity, even though many of those elements are called <a href="/wiki/Nonmetal_(chemistry)" class="mw-redirect" title="Nonmetal (chemistry)">nonmetals</a> in chemistry. </p> <style data-mw-deduplicate="TemplateStyles:r886046785">.mw-parser-output .toclimit-2 .toclevel-1 ul,.mw-parser-output .toclimit-3 .toclevel-2 ul,.mw-parser-output .toclimit-4 .toclevel-3 ul,.mw-parser-output .toclimit-5 .toclevel-4 ul,.mw-parser-output .toclimit-6 .toclevel-5 ul,.mw-parser-output .toclimit-7 .toclevel-6 ul{display:none}</style><div class="toclimit-2"><meta property="mw:PageProp/toc" /></div> <div class="mw-heading mw-heading2"><h2 id="Metals_in_early_spectroscopy">Metals in early spectroscopy</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Metallicity&action=edit&section=1" title="Edit section: Metals in early spectroscopy"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Fraunhofer_lines.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/2f/Fraunhofer_lines.svg/350px-Fraunhofer_lines.svg.png" decoding="async" width="350" height="103" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/2f/Fraunhofer_lines.svg/525px-Fraunhofer_lines.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/2f/Fraunhofer_lines.svg/700px-Fraunhofer_lines.svg.png 2x" data-file-width="768" data-file-height="225" /></a><figcaption>Solar spectrum with Fraunhofer lines as it appears visually.</figcaption></figure> <p>In 1802, <a href="/wiki/William_Hyde_Wollaston" title="William Hyde Wollaston">William Hyde Wollaston</a><sup id="cite_ref-eb_1-0" class="reference"><a href="#cite_note-eb-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> noted the appearance of a number of dark features in the solar spectrum.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> In 1814, <a href="/wiki/Joseph_von_Fraunhofer" title="Joseph von Fraunhofer">Joseph von Fraunhofer</a> independently rediscovered the lines and began to systematically study and measure their <a href="/wiki/Wavelength" title="Wavelength">wavelengths</a>, and they are now called <a href="/wiki/Fraunhofer_lines" title="Fraunhofer lines">Fraunhofer lines</a>. He mapped over 570 lines, designating the most prominent with the letters A through K and weaker lines with other letters.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p><p>About 45 years later, <a href="/wiki/Gustav_Kirchhoff" title="Gustav Kirchhoff">Gustav Kirchhoff</a> and <a href="/wiki/Robert_Bunsen" title="Robert Bunsen">Robert Bunsen</a><sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> noticed that several Fraunhofer lines coincide with characteristic <a href="/wiki/Emission_spectrum" title="Emission spectrum">emission lines</a> identifies in the spectra of heated chemical elements.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> They inferred that dark lines in the solar spectrum are caused by <a href="/wiki/Absorption_(electromagnetic_radiation)" title="Absorption (electromagnetic radiation)">absorption</a> by <a href="/wiki/Chemical_element" title="Chemical element">chemical elements</a> in the solar atmosphere.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> Their observations<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> were in the visible range where the strongest lines come from metals such as sodium, potassium, and iron.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> In the early work on the chemical composition of the sun the only elements that were detected in spectra were hydrogen and various metals,<sup id="cite_ref-Meadows_11-0" class="reference"><a href="#cite_note-Meadows-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Pages: 23–24">: 23–24 </span></sup> with the term <i>metallic</i> frequently used when describing them.<sup id="cite_ref-Meadows_11-1" class="reference"><a href="#cite_note-Meadows-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Location: Part 2">: Part 2 </span></sup> In contemporary usage in astronomy all the extra elements beyond just hydrogen and helium are termed metallic. </p> <div class="mw-heading mw-heading2"><h2 id="Origin_of_metallic_elements">Origin of metallic elements</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Metallicity&action=edit&section=2" title="Edit section: Origin of metallic elements"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Stellar_nucleosynthesis" title="Stellar nucleosynthesis">Stellar nucleosynthesis</a> and <a href="/wiki/Big_Bang_nucleosynthesis" title="Big Bang nucleosynthesis">Big Bang nucleosynthesis</a></div> <p>The presence of heavier elements results from stellar nucleosynthesis, where the majority of elements heavier than hydrogen and helium in the Universe (<i>metals</i>, hereafter) are formed in the cores of stars as they <a href="/wiki/Stellar_evolution" title="Stellar evolution">evolve</a>. Over time, <a href="/wiki/Stellar_wind" title="Stellar wind">stellar winds</a> and <a href="/wiki/Supernova" title="Supernova">supernovae</a> deposit the metals into the surrounding environment, enriching the <a href="/wiki/Interstellar_medium" title="Interstellar medium">interstellar medium</a> and providing recycling materials for the <a href="/wiki/Protostar" title="Protostar">birth of new stars</a>. It follows that older generations of stars, which formed in the metal-poor <a href="/wiki/Chronology_of_the_universe" title="Chronology of the universe">early Universe</a>, generally have lower metallicities than those of younger generations, which formed in a more metal-rich Universe. </p> <div class="mw-heading mw-heading2"><h2 id="Stellar_populations">Stellar populations</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Metallicity&action=edit&section=3" title="Edit section: Stellar populations"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Treasures3.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Treasures3.jpg/220px-Treasures3.jpg" decoding="async" width="220" height="300" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Treasures3.jpg/330px-Treasures3.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Treasures3.jpg/440px-Treasures3.jpg 2x" data-file-width="940" data-file-height="1280" /></a><figcaption><a href="/wiki/Population_I" class="mw-redirect" title="Population I">Population I</a> star <a href="/wiki/Rigel" title="Rigel">Rigel</a> with <a href="/wiki/Reflection_nebula" title="Reflection nebula">reflection nebula</a> <a href="/wiki/IC_2118" title="IC 2118">IC 2118</a></figcaption></figure> <p>Observed changes in the chemical abundances of different types of stars, based on the spectral peculiarities that were later attributed to metallicity, led astronomer <a href="/wiki/Walter_Baade" title="Walter Baade">Walter Baade</a> in 1944 to propose the existence of two different <a href="/wiki/Stellar_population" title="Stellar population">populations of stars</a>.<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> These became commonly known as <span class="nowrap"><a href="/wiki/Population_I" class="mw-redirect" title="Population I">population I</a></span> (metal-rich) and <span class="nowrap"><a href="/wiki/Population_II" class="mw-redirect" title="Population II">population II</a></span> (metal-poor) stars. A third, earliest <a href="/wiki/Stellar_population" title="Stellar population">stellar population</a> was hypothesized in 1978, known as <span class="nowrap"><a href="/wiki/Population_III" class="mw-redirect" title="Population III">population III</a></span> stars.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> These "extremely metal-poor" (XMP) stars are theorized to have been the "first-born" stars created in the Universe. </p> <div class="mw-heading mw-heading2"><h2 id="Common_methods_of_calculation">Common methods of calculation</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Metallicity&action=edit&section=4" title="Edit section: Common methods of calculation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Astronomers use several different methods to describe and approximate metal abundances, depending on the available tools and the object of interest. Some methods include determining the fraction of mass that is attributed to <a href="/wiki/Gas" title="Gas">gas</a> versus metals, or measuring the ratios of the number of atoms of two different elements as compared to the ratios found in the <a href="/wiki/Sun" title="Sun">Sun</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Mass_fraction">Mass fraction</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Metallicity&action=edit&section=5" title="Edit section: Mass fraction"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Stellar composition is often simply defined by the parameters <span class="texhtml mvar" style="font-style:italic;">X</span>, <span class="texhtml mvar" style="font-style:italic;">Y</span>, and <span class="texhtml mvar" style="font-style:italic;">Z</span>. Here <span class="texhtml mvar" style="font-style:italic;">X</span> represents the mass fraction of <a href="/wiki/Hydrogen" title="Hydrogen">hydrogen</a>, <span class="texhtml mvar" style="font-style:italic;">Y</span> is the mass fraction of <a href="/wiki/Helium" title="Helium">helium</a>, and <span class="texhtml mvar" style="font-style:italic;">Z</span> is the mass fraction of all the remaining chemical elements. Thus </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle X+Y+Z=1}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>X</mi> <mo>+</mo> <mi>Y</mi> <mo>+</mo> <mi>Z</mi> <mo>=</mo> <mn>1</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle X+Y+Z=1}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b11c6e06a8964ed3dfce909f6418bd4caf850559" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.505ex; width:15.375ex; height:2.343ex;" alt="{\displaystyle X+Y+Z=1}"></span> </p><p>In most <a href="/wiki/Stars" class="mw-redirect" title="Stars">stars</a>, <a href="/wiki/Nebula" title="Nebula">nebulae</a>, <a href="/wiki/H_II_region" title="H II region">H<sup>II</sup> regions</a>, and other astronomical sources, hydrogen and helium are the two dominant elements. The hydrogen mass fraction is generally expressed as <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ X\equiv {\tfrac {m_{\mathsf {H}}}{M}}\ ,}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <mi>X</mi> <mo>≡</mo> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mfrac> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> </mrow> </mrow> </msub> <mi>M</mi> </mfrac> </mstyle> </mrow> <mtext> </mtext> <mo>,</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ X\equiv {\tfrac {m_{\mathsf {H}}}{M}}\ ,}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/c74f667b02ba256dc9c4d1104f646246e1c07da1" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.171ex; width:10.274ex; height:3.509ex;" alt="{\displaystyle \ X\equiv {\tfrac {m_{\mathsf {H}}}{M}}\ ,}"></span> where <span class="texhtml mvar" style="font-style:italic;">M</span> is the total mass of the system, and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ m_{\mathsf {H}}\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> </mrow> </mrow> </msub> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ m_{\mathsf {H}}\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/caac3a02d160d56b04ab1688da36c09505109399" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:4.598ex; height:2.009ex;" alt="{\displaystyle \ m_{\mathsf {H}}\ }"></span> is the mass of the hydrogen it contains. Similarly, the helium mass fraction is denoted as <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ Y\equiv {\tfrac {m_{\mathsf {He}}}{M}}~.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <mi>Y</mi> <mo>≡</mo> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mfrac> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> <mi mathvariant="sans-serif">e</mi> </mrow> </mrow> </msub> <mi>M</mi> </mfrac> </mstyle> </mrow> <mtext> </mtext> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ Y\equiv {\tfrac {m_{\mathsf {He}}}{M}}~.}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/2ef48beaad71fdbea048734f7e631d61eb8b0d0e" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.171ex; width:10.66ex; height:3.509ex;" alt="{\displaystyle \ Y\equiv {\tfrac {m_{\mathsf {He}}}{M}}~.}"></span> The remainder of the elements are collectively referred to as "metals", and the mass fraction of metals is calculated as </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle Z=\sum _{e>{\mathsf {He}}}{\tfrac {m_{e}}{M}}=1-X-Y~.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>Z</mi> <mo>=</mo> <munder> <mo>∑</mo> <mrow class="MJX-TeXAtom-ORD"> <mi>e</mi> <mo>></mo> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> <mi mathvariant="sans-serif">e</mi> </mrow> </mrow> </mrow> </munder> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mfrac> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>e</mi> </mrow> </msub> <mi>M</mi> </mfrac> </mstyle> </mrow> <mo>=</mo> <mn>1</mn> <mo>−</mo> <mi>X</mi> <mo>−</mo> <mi>Y</mi> <mtext> </mtext> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle Z=\sum _{e>{\mathsf {He}}}{\tfrac {m_{e}}{M}}=1-X-Y~.}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/4252e32d18d533a40ee2857ecf6389901452304e" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -3.171ex; width:27.092ex; height:5.676ex;" alt="{\displaystyle Z=\sum _{e>{\mathsf {He}}}{\tfrac {m_{e}}{M}}=1-X-Y~.}"></span> </p><p>For the surface of the Sun (<a href="/wiki/Astronomical_symbols" title="Astronomical symbols">symbol</a> <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \odot }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo>⊙</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \odot }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/e89e009eb8a8839c82aa5c76c15e9f2d67006276" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.505ex; width:1.808ex; height:2.176ex;" alt="{\displaystyle \odot }"></span>), these parameters are measured to have the following values:<sup id="cite_ref-asplund_16-0" class="reference"><a href="#cite_note-asplund-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> </p> <table class="wikitable"> <tbody><tr> <th>Description</th> <th>Solar value </th></tr> <tr> <td>Hydrogen mass fraction</td> <td><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ X_{\odot }=0.7381\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <msub> <mi>X</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>⊙</mo> </mrow> </msub> <mo>=</mo> <mn>0.7381</mn> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ X_{\odot }=0.7381\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/0e962f2d70cb33abc99f73bfe09323a7acbda509" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:14.154ex; height:2.509ex;" alt="{\displaystyle \ X_{\odot }=0.7381\ }"></span> </td></tr> <tr> <td>Helium mass fraction</td> <td><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ Y_{\odot }=0.2485\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <msub> <mi>Y</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>⊙</mo> </mrow> </msub> <mo>=</mo> <mn>0.2485</mn> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ Y_{\odot }=0.2485\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/7c29aecfeb635d5835011eb7e0f57d130a60ae63" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:13.58ex; height:2.509ex;" alt="{\displaystyle \ Y_{\odot }=0.2485\ }"></span> </td></tr> <tr> <td>Metal mass fraction</td> <td><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ Z_{\odot }=0.0134\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <msub> <mi>Z</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>⊙</mo> </mrow> </msub> <mo>=</mo> <mn>0.0134</mn> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ Z_{\odot }=0.0134\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/09c8424275105eec538817554d5916c48ec41c49" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:13.817ex; height:2.509ex;" alt="{\displaystyle \ Z_{\odot }=0.0134\ }"></span> </td></tr></tbody></table> <p>Due to the effects of <a href="/wiki/Stellar_evolution" title="Stellar evolution">stellar evolution</a>, neither the initial composition nor the present day bulk composition of the Sun is the same as its present-day surface composition. </p> <div class="mw-heading mw-heading3"><h3 id="Chemical_abundance_ratios">Chemical abundance ratios</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Metallicity&action=edit&section=6" title="Edit section: Chemical abundance ratios"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The overall stellar metallicity is conventionally defined using the total hydrogen content, since its abundance is considered to be relatively constant in the Universe, or the <a href="/wiki/Iron" title="Iron">iron</a> content of the star, which has an abundance that is generally linearly increasing in time in the Universe.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> Hence, iron can be used as a chronological indicator of nucleosynthesis. <a href="/wiki/Iron" title="Iron">Iron</a> is relatively easy to measure with spectral observations in the star's spectrum given the large number of iron lines in the star's spectra (even though oxygen is the <a href="/wiki/Abundance_of_the_chemical_elements#Universe" title="Abundance of the chemical elements">most abundant heavy element</a> – see <a href="#H-II-region-anchor">metallicities in H<sup>II</sup> regions</a> below). The abundance ratio is the <a href="/wiki/Common_logarithm" title="Common logarithm">common logarithm</a> of the ratio of a star's iron abundance compared to that of the Sun and is calculated thus:<sup id="cite_ref-Matteucci2001_18-0" class="reference"><a href="#cite_note-Matteucci2001-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \left[{\frac {\mathsf {Fe}}{\mathsf {H}}}\right]~=~\log _{10}{\left({\frac {N_{\mathsf {Fe}}}{N_{\mathsf {H}}}}\right)_{\star }}-~\log _{10}{\left({\frac {N_{\mathsf {Fe}}}{N_{\mathsf {H}}}}\right)_{\odot }}\ ,}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow> <mo>[</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">F</mi> <mi mathvariant="sans-serif">e</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> </mrow> </mfrac> </mrow> <mo>]</mo> </mrow> <mtext> </mtext> <mo>=</mo> <mtext> </mtext> <msub> <mi>log</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>10</mn> </mrow> </msub> <mo>⁡</mo> <mrow class="MJX-TeXAtom-ORD"> <msub> <mrow> <mo>(</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <msub> <mi>N</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">F</mi> <mi mathvariant="sans-serif">e</mi> </mrow> </mrow> </msub> <msub> <mi>N</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> </mrow> </mrow> </msub> </mfrac> </mrow> <mo>)</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mo>⋆</mo> </mrow> </msub> </mrow> <mo>−</mo> <mtext> </mtext> <msub> <mi>log</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>10</mn> </mrow> </msub> <mo>⁡</mo> <mrow class="MJX-TeXAtom-ORD"> <msub> <mrow> <mo>(</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <msub> <mi>N</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">F</mi> <mi mathvariant="sans-serif">e</mi> </mrow> </mrow> </msub> <msub> <mi>N</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> </mrow> </mrow> </msub> </mfrac> </mrow> <mo>)</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mo>⊙</mo> </mrow> </msub> </mrow> <mtext> </mtext> <mo>,</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \left[{\frac {\mathsf {Fe}}{\mathsf {H}}}\right]~=~\log _{10}{\left({\frac {N_{\mathsf {Fe}}}{N_{\mathsf {H}}}}\right)_{\star }}-~\log _{10}{\left({\frac {N_{\mathsf {Fe}}}{N_{\mathsf {H}}}}\right)_{\odot }}\ ,}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/00a53cde09129128faa7e4d630374bd45b9817c4" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.671ex; width:44.793ex; height:6.343ex;" alt="{\displaystyle \left[{\frac {\mathsf {Fe}}{\mathsf {H}}}\right]~=~\log _{10}{\left({\frac {N_{\mathsf {Fe}}}{N_{\mathsf {H}}}}\right)_{\star }}-~\log _{10}{\left({\frac {N_{\mathsf {Fe}}}{N_{\mathsf {H}}}}\right)_{\odot }}\ ,}"></span> </p><p>where <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ N_{\mathsf {Fe}}\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <msub> <mi>N</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">F</mi> <mi mathvariant="sans-serif">e</mi> </mrow> </mrow> </msub> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ N_{\mathsf {Fe}}\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f16d4b78414b60893881f245a03ab05407260a22" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:4.925ex; height:2.509ex;" alt="{\displaystyle \ N_{\mathsf {Fe}}\ }"></span> and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ N_{\mathsf {H}}\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <msub> <mi>N</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> </mrow> </mrow> </msub> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ N_{\mathsf {H}}\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/872b0d4c7fa6873ae0665defa223ec78ac57f350" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:4.423ex; height:2.509ex;" alt="{\displaystyle \ N_{\mathsf {H}}\ }"></span> are the number of iron and hydrogen atoms per unit of volume respectively, <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \odot }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo>⊙</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \odot }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/e89e009eb8a8839c82aa5c76c15e9f2d67006276" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.505ex; width:1.808ex; height:2.176ex;" alt="{\displaystyle \odot }"></span> is the <a href="/wiki/Astronomical_symbols" title="Astronomical symbols">standard symbol</a> for the Sun, and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \star }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo>⋆</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \star }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/bd316a21eeb5079a850f223b1d096a06bfa788c0" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: 0.035ex; margin-bottom: -0.206ex; width:1.162ex; height:1.509ex;" alt="{\displaystyle \star }"></span> for a star (often omitted below). The unit often used for metallicity is the <a href="/wiki/Dex_(decimal_exponent)" title="Dex (decimal exponent)">dex</a>, contraction of "decimal exponent".<sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> By this formulation, stars with a higher metallicity than the Sun have a positive <a href="/wiki/Common_logarithm" title="Common logarithm">common logarithm</a>, whereas those more dominated by hydrogen have a corresponding negative value. For example, stars with a <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}_{\star }\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-OPEN"> <mo maxsize="1.2em" minsize="1.2em">[</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mfrac> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">F</mi> <mi mathvariant="sans-serif">e</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> </mrow> </mfrac> </mstyle> </mrow> <msub> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-CLOSE"> <mo maxsize="1.2em" minsize="1.2em">]</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mo>⋆</mo> </mrow> </msub> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}_{\star }\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/5392288ee560cfde9f1b75201a21e4d7bf1f6ec6" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.338ex; width:6.656ex; height:3.843ex;" alt="{\displaystyle \ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}_{\star }\ }"></span> value of +1 have 10 times the metallicity of the Sun (10<sup><span class="nowrap"><span data-sort-value="7000100000000000000♠"></span>+1</span></sup>); conversely, those with a <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}_{\star }\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-OPEN"> <mo maxsize="1.2em" minsize="1.2em">[</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mfrac> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">F</mi> <mi mathvariant="sans-serif">e</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> </mrow> </mfrac> </mstyle> </mrow> <msub> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-CLOSE"> <mo maxsize="1.2em" minsize="1.2em">]</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mo>⋆</mo> </mrow> </msub> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}_{\star }\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/5392288ee560cfde9f1b75201a21e4d7bf1f6ec6" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.338ex; width:6.656ex; height:3.843ex;" alt="{\displaystyle \ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}_{\star }\ }"></span> value of −1 have <style data-mw-deduplicate="TemplateStyles:r1214402035">.mw-parser-output .sfrac{white-space:nowrap}.mw-parser-output .sfrac.tion,.mw-parser-output .sfrac .tion{display:inline-block;vertical-align:-0.5em;font-size:85%;text-align:center}.mw-parser-output .sfrac .num{display:block;line-height:1em;margin:0.0em 0.1em;border-bottom:1px solid}.mw-parser-output .sfrac .den{display:block;line-height:1em;margin:0.1em 0.1em}.mw-parser-output .sr-only{border:0;clip:rect(0,0,0,0);clip-path:polygon(0px 0px,0px 0px,0px 0px);height:1px;margin:-1px;overflow:hidden;padding:0;position:absolute;width:1px}</style><span class="sfrac">⁠<span class="tion"><span class="num">1</span><span class="sr-only">/</span><span class="den">10</span></span>⁠</span>, while those with a <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}_{\star }\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-OPEN"> <mo maxsize="1.2em" minsize="1.2em">[</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mfrac> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">F</mi> <mi mathvariant="sans-serif">e</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> </mrow> </mfrac> </mstyle> </mrow> <msub> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-CLOSE"> <mo maxsize="1.2em" minsize="1.2em">]</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mo>⋆</mo> </mrow> </msub> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}_{\star }\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/5392288ee560cfde9f1b75201a21e4d7bf1f6ec6" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.338ex; width:6.656ex; height:3.843ex;" alt="{\displaystyle \ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}_{\star }\ }"></span> value of 0 have the same metallicity as the Sun, and so on.<sup id="cite_ref-Martin_20-0" class="reference"><a href="#cite_note-Martin-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> </p><p>Young population I stars have significantly higher iron-to-hydrogen ratios than older population II stars. Primordial <a href="/wiki/Stellar_population#Population_III_stars" title="Stellar population">population III</a> stars are estimated to have metallicity less than −6, a millionth of the abundance of iron in the Sun.<sup id="cite_ref-AJ-20150604_21-0" class="reference"><a href="#cite_note-AJ-20150604-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-NYT-20150617_22-0" class="reference"><a href="#cite_note-NYT-20150617-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> The same notation is used to express variations in abundances between other individual elements as compared to solar proportions. For example, the notation <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ {\bigl [}{\tfrac {\mathsf {O}}{\mathsf {Fe}}}{\bigr ]}\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-OPEN"> <mo maxsize="1.2em" minsize="1.2em">[</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mfrac> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">O</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">F</mi> <mi mathvariant="sans-serif">e</mi> </mrow> </mfrac> </mstyle> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-CLOSE"> <mo maxsize="1.2em" minsize="1.2em">]</mo> </mrow> </mrow> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ {\bigl [}{\tfrac {\mathsf {O}}{\mathsf {Fe}}}{\bigr ]}\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/c015be8a2e9e300b36dfbb4dd5893bb879eefcfd" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.338ex; width:5.602ex; height:3.843ex;" alt="{\displaystyle \ {\bigl [}{\tfrac {\mathsf {O}}{\mathsf {Fe}}}{\bigr ]}\ }"></span> represents the difference in the logarithm of the star's oxygen abundance versus its iron content compared to that of the Sun. In general, a given <a href="/wiki/Stellar_nucleosynthesis" title="Stellar nucleosynthesis">stellar nucleosynthetic</a> process alters the proportions of only a few elements or isotopes, so a star or gas sample with certain <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ {\bigl [}{\tfrac {\mathsf {?}}{\mathsf {Fe}}}{\bigr ]}_{\star }\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-OPEN"> <mo maxsize="1.2em" minsize="1.2em">[</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mfrac> <mrow class="MJX-TeXAtom-ORD"> <mo mathvariant="sans-serif">?</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">F</mi> <mi mathvariant="sans-serif">e</mi> </mrow> </mfrac> </mstyle> </mrow> <msub> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-CLOSE"> <mo maxsize="1.2em" minsize="1.2em">]</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mo>⋆</mo> </mrow> </msub> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ {\bigl [}{\tfrac {\mathsf {?}}{\mathsf {Fe}}}{\bigr ]}_{\star }\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b65d0d0ba6bf094444e4fa3ba7c5bf4d761e3b86" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.338ex; width:6.656ex; height:3.843ex;" alt="{\displaystyle \ {\bigl [}{\tfrac {\mathsf {?}}{\mathsf {Fe}}}{\bigr ]}_{\star }\ }"></span> values may well be indicative of an associated, studied nuclear process. </p> <div class="mw-heading mw-heading3"><h3 id="Photometric_colors">Photometric colors</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Metallicity&action=edit&section=7" title="Edit section: Photometric colors"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Astronomers can estimate metallicities through measured and calibrated systems that correlate <a href="/wiki/Photometry_(astronomy)" title="Photometry (astronomy)">photometric measurements</a> and <a href="/wiki/Spectroscopy" title="Spectroscopy">spectroscopic measurements</a> (see also <a href="/wiki/Spectrophotometry" title="Spectrophotometry">Spectrophotometry</a>). For example, the <a href="/wiki/UBV_photometric_system" title="UBV photometric system">Johnson UVB filters</a> can be used to detect an <a href="/wiki/Ultraviolet" title="Ultraviolet">ultraviolet</a> (UV) excess in stars,<sup id="cite_ref-23" class="reference"><a href="#cite_note-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> where a smaller UV excess indicates a larger presence of metals that absorb the UV radiation, thereby making the star appear "redder".<sup id="cite_ref-24" class="reference"><a href="#cite_note-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> The UV excess, <span class="texhtml mvar" style="font-style:italic;">δ</span>(U−B), is defined as the difference between a star's U and B band <a href="/wiki/Magnitude_(astronomy)" title="Magnitude (astronomy)">magnitudes</a>, compared to the difference between U and B band magnitudes of metal-rich stars in the <a href="/wiki/Hyades_(star_cluster)" title="Hyades (star cluster)">Hyades cluster</a>.<sup id="cite_ref-Wildey-Burbidge-etal-1962_27-0" class="reference"><a href="#cite_note-Wildey-Burbidge-etal-1962-27"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> Unfortunately, <span class="texhtml mvar" style="font-style:italic;">δ</span>(U−B) is sensitive to both metallicity and <a href="/wiki/Effective_temperature" title="Effective temperature">temperature</a>: If two stars are equally metal-rich, but one is cooler than the other, they will likely have different <span class="texhtml mvar" style="font-style:italic;">δ</span>(U−B) values<sup id="cite_ref-Wildey-Burbidge-etal-1962_27-1" class="reference"><a href="#cite_note-Wildey-Burbidge-etal-1962-27"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> (see also <a href="/wiki/Blanketing_effect" title="Blanketing effect">Blanketing effect</a><sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-29" class="reference"><a href="#cite_note-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup>). To help mitigate this degeneracy, a star's B−V <a href="/wiki/Color_index" title="Color index">color index</a> can be used as an indicator for temperature. Furthermore, the UV excess and B−V index can be corrected to relate the <span class="texhtml mvar" style="font-style:italic;">δ</span>(U−B) value to iron abundances.<sup id="cite_ref-30" class="reference"><a href="#cite_note-30"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-32" class="reference"><a href="#cite_note-32"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup> </p><p>Other <a href="/wiki/Photometric_system" title="Photometric system">photometric systems</a> that can be used to determine metallicities of certain astrophysical objects include the Strӧmgren system,<sup id="cite_ref-33" class="reference"><a href="#cite_note-33"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-34" class="reference"><a href="#cite_note-34"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup> the Geneva system,<sup id="cite_ref-35" class="reference"><a href="#cite_note-35"><span class="cite-bracket">[</span>35<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-36" class="reference"><a href="#cite_note-36"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup> the Washington system,<sup id="cite_ref-37" class="reference"><a href="#cite_note-37"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-38" class="reference"><a href="#cite_note-38"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup> and the DDO system.<sup id="cite_ref-39" class="reference"><a href="#cite_note-39"><span class="cite-bracket">[</span>39<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-40" class="reference"><a href="#cite_note-40"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Metallicities_in_various_astrophysical_objects">Metallicities in various astrophysical objects</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Metallicity&action=edit&section=8" title="Edit section: Metallicities in various astrophysical objects"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Stars">Stars</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Metallicity&action=edit&section=9" title="Edit section: Stars"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>At a given mass and age, a metal-poor star will be slightly warmer. <span class="nowrap"><a href="/wiki/Population_II_star" class="mw-redirect" title="Population II star">Population II stars</a>'</span> metallicities are roughly <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035"><span class="sfrac">⁠<span class="tion"><span class="num">1</span><span class="sr-only">/</span><span class="den">1000</span></span>⁠</span> to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035"><span class="sfrac">⁠<span class="tion"><span class="num">1</span><span class="sr-only">/</span><span class="den">10</span></span>⁠</span> of the Sun's <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \left(\ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}\ ={-3.0}\ ...\ {-1.0}\ \right)\ ,}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow> <mo>(</mo> <mrow> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-OPEN"> <mo maxsize="1.2em" minsize="1.2em">[</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mfrac> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">F</mi> <mi mathvariant="sans-serif">e</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> </mrow> </mfrac> </mstyle> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-CLOSE"> <mo maxsize="1.2em" minsize="1.2em">]</mo> </mrow> </mrow> <mtext> </mtext> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mo>−</mo> <mn>3.0</mn> </mrow> <mtext> </mtext> <mo>.</mo> <mo>.</mo> <mo>.</mo> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mo>−</mo> <mn>1.0</mn> </mrow> <mtext> </mtext> </mrow> <mo>)</mo> </mrow> <mtext> </mtext> <mo>,</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \left(\ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}\ ={-3.0}\ ...\ {-1.0}\ \right)\ ,}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/93d35c7995598257c64bab5a8654f8f97024aa48" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:27.494ex; height:4.843ex;" alt="{\displaystyle \left(\ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}\ ={-3.0}\ ...\ {-1.0}\ \right)\ ,}"></span> but the group appears cooler than <span class="nowrap">population I</span> overall, as heavy population II stars have long since died. Above 40 <a href="/wiki/Solar_mass" title="Solar mass">solar masses</a>, metallicity influences how a star will die: Outside the <a href="/wiki/Pair-instability_supernova" title="Pair-instability supernova">pair-instability window</a>, lower metallicity stars will collapse directly to a black hole, while higher metallicity stars undergo a <a href="/wiki/Core-collapse_supernova" class="mw-redirect" title="Core-collapse supernova">type Ib/c supernova</a> and may leave a <a href="/wiki/Neutron_star" title="Neutron star">neutron star</a>. </p> <div class="mw-heading mw-heading4"><h4 id="Relationship_between_stellar_metallicity_and_planets">Relationship between stellar metallicity and planets</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Metallicity&action=edit&section=10" title="Edit section: Relationship between stellar metallicity and planets"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A star's metallicity measurement is one parameter that helps determine whether a star may have a giant <a href="/wiki/Planet" title="Planet">planet</a>, as there is a direct correlation between metallicity and the presence of a giant planet. Measurements have demonstrated the connection between a star's metallicity and <a href="/wiki/Gas_giant" title="Gas giant">gas giant</a> planets, like <a href="/wiki/Jupiter" title="Jupiter">Jupiter</a> and <a href="/wiki/Saturn" title="Saturn">Saturn</a>. The more metals in a star and thus its <a href="/wiki/Planetary_system" title="Planetary system">planetary system</a> and <a href="/wiki/Protoplanetary_disk" title="Protoplanetary disk">protoplanetary disk</a>, the more likely the system may have gas giant planets. Current models show that the metallicity along with the correct planetary system temperature and distance from the star are key to planet and <a href="/wiki/Planetesimal" title="Planetesimal">planetesimal</a> formation. For two stars that have equal age and mass but different metallicity, the less metallic star is <a href="/wiki/Stellar_classification" title="Stellar classification">bluer</a>. Among stars of the same color, less metallic stars emit more ultraviolet radiation. The Sun, with <a href="/wiki/Solar_System#Planets" title="Solar System">eight planets</a> and nine consensus <a href="/wiki/Dwarf_planets" class="mw-redirect" title="Dwarf planets">dwarf planets</a>, is used as the reference, with a <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-OPEN"> <mo maxsize="1.2em" minsize="1.2em">[</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mfrac> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">F</mi> <mi mathvariant="sans-serif">e</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> </mrow> </mfrac> </mstyle> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-CLOSE"> <mo maxsize="1.2em" minsize="1.2em">]</mo> </mrow> </mrow> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/119adfa3ad9bd74448f8880ce03919f53a1b7b35" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.338ex; width:5.602ex; height:3.843ex;" alt="{\displaystyle \ {\bigl [}{\tfrac {\mathsf {Fe}}{\mathsf {H}}}{\bigr ]}\ }"></span> of 0.00.<sup id="cite_ref-41" class="reference"><a href="#cite_note-41"><span class="cite-bracket">[</span>41<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-42" class="reference"><a href="#cite_note-42"><span class="cite-bracket">[</span>42<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-43" class="reference"><a href="#cite_note-43"><span class="cite-bracket">[</span>43<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-44" class="reference"><a href="#cite_note-44"><span class="cite-bracket">[</span>44<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-45" class="reference"><a href="#cite_note-45"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading4"><h4 id="HII_regions"><span class="anchor" id="H-II-region-anchor">H<sup>II</sup> regions</span></h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Metallicity&action=edit&section=11" title="Edit section: HII regions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Young, massive and hot stars (typically of spectral types <a href="/wiki/O-type_star" title="O-type star">O</a> and <a href="/wiki/B-type_main-sequence_star" title="B-type main-sequence star">B</a>) in <a href="/wiki/H_II_region" title="H II region">H<sup>II</sup> regions</a> emit <a href="/wiki/Ultraviolet" title="Ultraviolet">UV photons</a> that ionize <a href="/wiki/Ground-state" class="mw-redirect" title="Ground-state">ground-state</a> hydrogen atoms, knocking <a href="/wiki/Electron" title="Electron">electrons</a> free; this process is known as <a href="/wiki/Photoionization" title="Photoionization">photoionization</a>. The free electrons can <a href="/wiki/Collisional_excitation" title="Collisional excitation">strike</a> other atoms nearby, exciting bound metallic electrons into a <a href="/wiki/Metastability" title="Metastability">metastable state</a>, which eventually decay back into a ground state, emitting photons with energies that correspond to <a href="/wiki/Forbidden_mechanism" title="Forbidden mechanism">forbidden lines</a>. Through these transitions, astronomers have developed several observational methods to estimate metal abundances in H<sup>II</sup> regions, where the stronger the forbidden lines in spectroscopic observations, the higher the metallicity.<sup id="cite_ref-46" class="reference"><a href="#cite_note-46"><span class="cite-bracket">[</span>46<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-47" class="reference"><a href="#cite_note-47"><span class="cite-bracket">[</span>47<span class="cite-bracket">]</span></a></sup> These methods are dependent on one or more of the following: the variety of asymmetrical densities inside H<sup>II</sup> regions, the varied temperatures of the embedded stars, and/or the electron density within the ionized region.<sup id="cite_ref-48" class="reference"><a href="#cite_note-48"><span class="cite-bracket">[</span>48<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-49" class="reference"><a href="#cite_note-49"><span class="cite-bracket">[</span>49<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-50" class="reference"><a href="#cite_note-50"><span class="cite-bracket">[</span>50<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-51" class="reference"><a href="#cite_note-51"><span class="cite-bracket">[</span>51<span class="cite-bracket">]</span></a></sup> </p><p>Theoretically, to determine the total abundance of a single element in an H<sup>II</sup> region, all transition lines should be observed and summed. However, this can be observationally difficult due to variation in line strength.<sup id="cite_ref-Grazyna-2004-Esteban-etal_52-0" class="reference"><a href="#cite_note-Grazyna-2004-Esteban-etal-52"><span class="cite-bracket">[</span>52<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-53" class="reference"><a href="#cite_note-53"><span class="cite-bracket">[</span>53<span class="cite-bracket">]</span></a></sup> Some of the most common forbidden lines used to determine metal abundances in H<sup>II</sup> regions are from <a href="/wiki/Oxygen" title="Oxygen">oxygen</a> (e.g. [O<sup>II</sup>] <span class="texhtml mvar" style="font-style:italic;">λ</span> = (3727, 7318, 7324) Å, and [O<sup>III</sup>] <span class="texhtml mvar" style="font-style:italic;">λ</span> = (4363, 4959, 5007) Å), <a href="/wiki/Nitrogen" title="Nitrogen">nitrogen</a> (e.g. [N<sup>II</sup>] <span class="texhtml mvar" style="font-style:italic;">λ</span> = (5755, 6548, 6584) Å), and <a href="/wiki/Sulfur" title="Sulfur">sulfur</a> (e.g. [S<sup>II</sup>] <span class="texhtml mvar" style="font-style:italic;">λ</span> = (6717, 6731) Å and [S<sup>III</sup>] <span class="texhtml mvar" style="font-style:italic;">λ</span> = (6312, 9069, 9531) Å) in the <a href="/wiki/Visible_spectrum" title="Visible spectrum">optical</a> spectrum, and the [O<sup>III</sup>] <span class="texhtml mvar" style="font-style:italic;">λ</span> = (52, 88) μm and [N<sup>III</sup>] <span class="texhtml mvar" style="font-style:italic;">λ</span> = 57 μm lines in the <a href="/wiki/Infrared_spectroscopy" title="Infrared spectroscopy">infrared</a> spectrum. <a href="/wiki/Oxygen" title="Oxygen">Oxygen</a> has some of the stronger, more abundant lines in H<sup>II</sup> regions, making it a main target for metallicity estimates within these objects. To calculate metal abundances in H<sup>II</sup> regions using oxygen <a href="/wiki/Flux" title="Flux">flux</a> measurements, astronomers often use the <span class="texhtml mvar" style="font-style:italic;">R</span><sub>23</sub> method, in which </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle R_{23}={\frac {\ \left[\ {\mathsf {O}}^{\mathsf {II}}\right]_{3727~\mathrm {\AA} }+\left[\ {\mathsf {O}}^{\mathsf {III}}\right]_{4959~\mathrm {\AA} +5007~\mathrm {\AA} }\ }{{\Bigl [}\ {\mathsf {H}}_{\mathsf {\beta }}{\Bigr ]}_{4861~\mathrm {\AA} }}}\ ,}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>R</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>23</mn> </mrow> </msub> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mtext> </mtext> <msub> <mrow> <mo>[</mo> <mrow> <mtext> </mtext> <msup> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">O</mi> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">I</mi> <mi mathvariant="sans-serif">I</mi> </mrow> </mrow> </msup> </mrow> <mo>]</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>3727</mn> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo>Å</mo> </mrow> </mrow> </mrow> </msub> <mo>+</mo> <msub> <mrow> <mo>[</mo> <mrow> <mtext> </mtext> <msup> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">O</mi> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">I</mi> <mi mathvariant="sans-serif">I</mi> <mi mathvariant="sans-serif">I</mi> </mrow> </mrow> </msup> </mrow> <mo>]</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>4959</mn> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo>Å</mo> </mrow> </mrow> <mo>+</mo> <mn>5007</mn> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo>Å</mo> </mrow> </mrow> </mrow> </msub> <mtext> </mtext> </mrow> <mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-OPEN"> <mo maxsize="1.623em" minsize="1.623em">[</mo> </mrow> </mrow> <mtext> </mtext> <msub> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi>β</mi> </mrow> </mrow> </msub> <msub> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-CLOSE"> <mo maxsize="1.623em" minsize="1.623em">]</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>4861</mn> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo>Å</mo> </mrow> </mrow> </mrow> </msub> </mrow> </mfrac> </mrow> <mtext> </mtext> <mo>,</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle R_{23}={\frac {\ \left[\ {\mathsf {O}}^{\mathsf {II}}\right]_{3727~\mathrm {\AA} }+\left[\ {\mathsf {O}}^{\mathsf {III}}\right]_{4959~\mathrm {\AA} +5007~\mathrm {\AA} }\ }{{\Bigl [}\ {\mathsf {H}}_{\mathsf {\beta }}{\Bigr ]}_{4861~\mathrm {\AA} }}}\ ,}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/07da4c3a43ade348a36e361088a39a6b06399c9a" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -5.338ex; width:40.882ex; height:11.843ex;" alt="{\displaystyle R_{23}={\frac {\ \left[\ {\mathsf {O}}^{\mathsf {II}}\right]_{3727~\mathrm {\AA} }+\left[\ {\mathsf {O}}^{\mathsf {III}}\right]_{4959~\mathrm {\AA} +5007~\mathrm {\AA} }\ }{{\Bigl [}\ {\mathsf {H}}_{\mathsf {\beta }}{\Bigr ]}_{4861~\mathrm {\AA} }}}\ ,}"></span> </p><p>where <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ \left[\ {\mathsf {O}}^{\mathsf {II}}\right]_{3727~\mathrm {\AA} }+\left[\ {\mathsf {O}}^{\mathsf {III}}\right]_{4959~\mathrm {\AA} +5007~\mathrm {\AA} }\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <msub> <mrow> <mo>[</mo> <mrow> <mtext> </mtext> <msup> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">O</mi> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">I</mi> <mi mathvariant="sans-serif">I</mi> </mrow> </mrow> </msup> </mrow> <mo>]</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>3727</mn> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo>Å</mo> </mrow> </mrow> </mrow> </msub> <mo>+</mo> <msub> <mrow> <mo>[</mo> <mrow> <mtext> </mtext> <msup> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">O</mi> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">I</mi> <mi mathvariant="sans-serif">I</mi> <mi mathvariant="sans-serif">I</mi> </mrow> </mrow> </msup> </mrow> <mo>]</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>4959</mn> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo>Å</mo> </mrow> </mrow> <mo>+</mo> <mn>5007</mn> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo>Å</mo> </mrow> </mrow> </mrow> </msub> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ \left[\ {\mathsf {O}}^{\mathsf {II}}\right]_{3727~\mathrm {\AA} }+\left[\ {\mathsf {O}}^{\mathsf {III}}\right]_{4959~\mathrm {\AA} +5007~\mathrm {\AA} }\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/4f79eac8a49f97e36df6a877d73f986e76e9cc5d" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.505ex; width:32.079ex; height:5.509ex;" alt="{\displaystyle \ \left[\ {\mathsf {O}}^{\mathsf {II}}\right]_{3727~\mathrm {\AA} }+\left[\ {\mathsf {O}}^{\mathsf {III}}\right]_{4959~\mathrm {\AA} +5007~\mathrm {\AA} }\ }"></span> is the sum of the fluxes from oxygen <a href="/wiki/Spectral_line" title="Spectral line">emission lines</a> measured at the <a href="/wiki/Rest_frame" title="Rest frame">rest frame</a> <span class="texhtml mvar" style="font-style:italic;">λ</span> = (3727, 4959 and 5007) Å wavelengths, divided by the flux from the <a href="/wiki/Balmer_series" title="Balmer series">Balmer series</a> H<sub>β</sub> emission line at the rest frame <span class="texhtml mvar" style="font-style:italic;">λ</span> = 4861 Å wavelength.<sup id="cite_ref-54" class="reference"><a href="#cite_note-54"><span class="cite-bracket">[</span>54<span class="cite-bracket">]</span></a></sup> This ratio is well defined through models and observational studies,<sup id="cite_ref-55" class="reference"><a href="#cite_note-55"><span class="cite-bracket">[</span>55<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-56" class="reference"><a href="#cite_note-56"><span class="cite-bracket">[</span>56<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-57" class="reference"><a href="#cite_note-57"><span class="cite-bracket">[</span>57<span class="cite-bracket">]</span></a></sup> but caution should be taken, as the ratio is often degenerate, providing both a low and high metallicity solution, which can be broken with additional line measurements.<sup id="cite_ref-58" class="reference"><a href="#cite_note-58"><span class="cite-bracket">[</span>58<span class="cite-bracket">]</span></a></sup> Similarly, other strong forbidden line ratios can be used, e.g. for sulfur, where<sup id="cite_ref-59" class="reference"><a href="#cite_note-59"><span class="cite-bracket">[</span>59<span class="cite-bracket">]</span></a></sup> </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle S_{23}={\frac {\ \left[\ {\mathsf {S}}^{\mathsf {II}}\right]_{6716~\mathrm {\AA} +6731~\mathrm {\AA} }+\left[\ {\mathsf {S}}^{\mathsf {III}}\right]_{9069~\mathrm {\AA} +9532~\mathrm {\AA} }\ }{{\Bigl [}\ {\mathsf {H}}_{\mathsf {\beta }}{\Bigr ]}_{4861~\mathrm {\AA} }}}~.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>S</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>23</mn> </mrow> </msub> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mtext> </mtext> <msub> <mrow> <mo>[</mo> <mrow> <mtext> </mtext> <msup> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">S</mi> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">I</mi> <mi mathvariant="sans-serif">I</mi> </mrow> </mrow> </msup> </mrow> <mo>]</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>6716</mn> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo>Å</mo> </mrow> </mrow> <mo>+</mo> <mn>6731</mn> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo>Å</mo> </mrow> </mrow> </mrow> </msub> <mo>+</mo> <msub> <mrow> <mo>[</mo> <mrow> <mtext> </mtext> <msup> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">S</mi> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">I</mi> <mi mathvariant="sans-serif">I</mi> <mi mathvariant="sans-serif">I</mi> </mrow> </mrow> </msup> </mrow> <mo>]</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>9069</mn> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo>Å</mo> </mrow> </mrow> <mo>+</mo> <mn>9532</mn> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo>Å</mo> </mrow> </mrow> </mrow> </msub> <mtext> </mtext> </mrow> <mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-OPEN"> <mo maxsize="1.623em" minsize="1.623em">[</mo> </mrow> </mrow> <mtext> </mtext> <msub> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="sans-serif">H</mi> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi>β</mi> </mrow> </mrow> </msub> <msub> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-CLOSE"> <mo maxsize="1.623em" minsize="1.623em">]</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>4861</mn> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo>Å</mo> </mrow> </mrow> </mrow> </msub> </mrow> </mfrac> </mrow> <mtext> </mtext> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle S_{23}={\frac {\ \left[\ {\mathsf {S}}^{\mathsf {II}}\right]_{6716~\mathrm {\AA} +6731~\mathrm {\AA} }+\left[\ {\mathsf {S}}^{\mathsf {III}}\right]_{9069~\mathrm {\AA} +9532~\mathrm {\AA} }\ }{{\Bigl [}\ {\mathsf {H}}_{\mathsf {\beta }}{\Bigr ]}_{4861~\mathrm {\AA} }}}~.}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b89b407869c9ac2f28790cfd83fa17960c81f7e2" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -5.338ex; width:45.855ex; height:11.843ex;" alt="{\displaystyle S_{23}={\frac {\ \left[\ {\mathsf {S}}^{\mathsf {II}}\right]_{6716~\mathrm {\AA} +6731~\mathrm {\AA} }+\left[\ {\mathsf {S}}^{\mathsf {III}}\right]_{9069~\mathrm {\AA} +9532~\mathrm {\AA} }\ }{{\Bigl [}\ {\mathsf {H}}_{\mathsf {\beta }}{\Bigr ]}_{4861~\mathrm {\AA} }}}~.}"></span> </p><p>Metal abundances within H<sup>II</sup> regions are typically less than 1%, with the percentage decreasing on average with distance from the <a href="/wiki/Galactic_Center" title="Galactic Center">Galactic Center</a>.<sup id="cite_ref-Grazyna-2004-Esteban-etal_52-1" class="reference"><a href="#cite_note-Grazyna-2004-Esteban-etal-52"><span class="cite-bracket">[</span>52<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-60" class="reference"><a href="#cite_note-60"><span class="cite-bracket">[</span>60<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-61" class="reference"><a href="#cite_note-61"><span class="cite-bracket">[</span>61<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-62" class="reference"><a href="#cite_note-62"><span class="cite-bracket">[</span>62<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-63" class="reference"><a href="#cite_note-63"><span class="cite-bracket">[</span>63<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Metallicity&action=edit&section=12" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Cosmos_Redshift_7" title="Cosmos Redshift 7">Cosmos Redshift 7</a>, a galaxy that reportedly contains Population III stars</li> <li><a href="/wiki/Galaxy_formation_and_evolution" title="Galaxy formation and evolution">Galaxy formation and evolution</a></li> <li><a href="/wiki/GRB_090423" title="GRB 090423">GRB 090423</a>, the most distant seen, presumably from a low-metallicity progenitor</li> <li><a href="/wiki/Metallicity_distribution_function" title="Metallicity distribution function">Metallicity distribution function</a></li></ul> <div style="clear:both;" class=""></div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Metallicity&action=edit&section=13" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-columns references-column-width" style="column-width: 25em;"> <ol class="references"> <li id="cite_note-eb-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-eb_1-0">^</a></b></span> <span class="reference-text">Melvyn C. Usselman: <a rel="nofollow" class="external text" href="http://www.britannica.com/EBchecked/topic/646649/William-Hyde-Wollaston">William Hyde Wollaston</a> Encyclopædia Britannica, retrieved 31 March 2013</span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text">William Hyde Wollaston (1802) <a rel="nofollow" class="external text" href="http://rstl.royalsocietypublishing.org/content/92/365.full.pdf+html">"A method of examining refractive and dispersive powers, by prismatic reflection,"</a> <i>Philosophical Transactions of the Royal Society</i>, <b>92</b>: 365–380; see especially p. 378.</span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFHearnshaw1986" class="citation book cs1">Hearnshaw, J.B. (1986). <i>The analysis of starlight</i>. Cambridge: <a href="/wiki/Cambridge_University_Press" title="Cambridge University Press">Cambridge University Press</a>. p. 27. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-521-39916-6" title="Special:BookSources/978-0-521-39916-6"><bdi>978-0-521-39916-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+analysis+of+starlight&rft.place=Cambridge&rft.pages=27&rft.pub=Cambridge+University+Press&rft.date=1986&rft.isbn=978-0-521-39916-6&rft.aulast=Hearnshaw&rft.aufirst=J.B.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text">Joseph Fraunhofer (1814 - 1815) <a rel="nofollow" class="external text" href="https://books.google.com/books?id=2-AAAAAAYAAJ&pg=PA203">"Bestimmung des Brechungs- und des Farben-Zerstreuungs - Vermögens verschiedener Glasarten, in Bezug auf die Vervollkommnung achromatischer Fernröhre"</a> (Determination of the refractive and color-dispersing power of different types of glass, in relation to the improvement of achromatic telescopes), <i>Denkschriften der Königlichen Akademie der Wissenschaften zu München</i> (Memoirs of the Royal Academy of Sciences in Munich), <b>5</b>: 193–226; see especially pages 202–205 and the plate following page 226.</span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJenkinsWhite1981" class="citation book cs1">Jenkins, Francis A.; White, Harvey E. (1981). <span class="id-lock-limited" title="Free access subject to limited trial, subscription normally required"><a rel="nofollow" class="external text" href="https://archive.org/details/fundamentalsopti00jenk"><i>Fundamentals of Optics</i></a></span> (4th ed.). <a href="/wiki/McGraw-Hill" class="mw-redirect" title="McGraw-Hill">McGraw-Hill</a>. p. <a rel="nofollow" class="external text" href="https://archive.org/details/fundamentalsopti00jenk/page/n37">18</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-07-256191-3" title="Special:BookSources/978-0-07-256191-3"><bdi>978-0-07-256191-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Fundamentals+of+Optics&rft.pages=18&rft.edition=4th&rft.pub=McGraw-Hill&rft.date=1981&rft.isbn=978-0-07-256191-3&rft.aulast=Jenkins&rft.aufirst=Francis+A.&rft.au=White%2C+Harvey+E.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Ffundamentalsopti00jenk&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text">See: <ul><li>Gustav Kirchhoff (1859) <a rel="nofollow" class="external text" href="https://books.google.com/books?id=CMgAAAAAYAAJ&pg=PA662">"Ueber die Fraunhofer'schen Linien"</a> (On Fraunhofer's lines), <i>Monatsbericht der Königlichen Preussische Akademie der Wissenschaften zu Berlin</i> (Monthly report of the Royal Prussian Academy of Sciences in Berlin), 662–665.</li> <li>Gustav Kirchhoff (1859) <a rel="nofollow" class="external text" href="https://books.google.com/books?id=uksDAAAAYAAJ&pg=RA1-PA251">"Ueber das Sonnenspektrum"</a> (On the sun's spectrum), <i>Verhandlungen des naturhistorisch-medizinischen Vereins zu Heidelberg</i> (Proceedings of the Natural History / Medical Association in Heidelberg), <b>1</b> (7) : 251–255.</li></ul> </span></li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFG._Kirchhoff1860" class="citation journal cs1">G. Kirchhoff (1860). <a rel="nofollow" class="external text" href="https://zenodo.org/record/1423666">"Ueber die Fraunhofer'schen Linien"</a>. <i>Annalen der Physik</i>. <b>185</b> (1): <span class="nowrap">148–</span>150. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1860AnP...185..148K">1860AnP...185..148K</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fandp.18601850115">10.1002/andp.18601850115</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Annalen+der+Physik&rft.atitle=Ueber+die+Fraunhofer%27schen+Linien&rft.volume=185&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E148-%3C%2Fspan%3E150&rft.date=1860&rft_id=info%3Adoi%2F10.1002%2Fandp.18601850115&rft_id=info%3Abibcode%2F1860AnP...185..148K&rft.au=G.+Kirchhoff&rft_id=https%3A%2F%2Fzenodo.org%2Frecord%2F1423666&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFG._Kirchhoff1860" class="citation journal cs1">G. Kirchhoff (1860). <a rel="nofollow" class="external text" href="https://zenodo.org/record/1423668">"Ueber das Verhältniss zwischen dem Emissionsvermögen und dem Absorptionsvermögen der Körper für Wärme und Licht"</a> [On the relation between the emissive power and the absorptive power of bodies towards heat and light]. <i>Annalen der Physik</i>. <b>185</b> (2): <span class="nowrap">275–</span>301. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1860AnP...185..275K">1860AnP...185..275K</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fandp.18601850205">10.1002/andp.18601850205</a></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Annalen+der+Physik&rft.atitle=Ueber+das+Verh%C3%A4ltniss+zwischen+dem+Emissionsverm%C3%B6gen+und+dem+Absorptionsverm%C3%B6gen+der+K%C3%B6rper+f%C3%BCr+W%C3%A4rme+und+Licht&rft.volume=185&rft.issue=2&rft.pages=%3Cspan+class%3D%22nowrap%22%3E275-%3C%2Fspan%3E301&rft.date=1860&rft_id=info%3Adoi%2F10.1002%2Fandp.18601850205&rft_id=info%3Abibcode%2F1860AnP...185..275K&rft.au=G.+Kirchhoff&rft_id=https%3A%2F%2Fzenodo.org%2Frecord%2F1423668&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.chemteam.info/Chem-History/Kirchhoff-Bunsen-1860.html">"Kirchhoff and Bunsen on Spectroscopy"</a>. <i>www.chemteam.info</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2024-07-02</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.chemteam.info&rft.atitle=Kirchhoff+and+Bunsen+on+Spectroscopy&rft_id=https%3A%2F%2Fwww.chemteam.info%2FChem-History%2FKirchhoff-Bunsen-1860.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://hdl.handle.net/2027/hvd.hn3317?urlappend=%3Bseq=211">"Spectrum analysis in its application to terrestrial substances and the physical constitution of the heavenly bodies : familiarly explained / by H. Schellen ..."</a> <i>HathiTrust</i>. <a href="/wiki/Hdl_(identifier)" class="mw-redirect" title="Hdl (identifier)">hdl</a>:<a rel="nofollow" class="external text" href="https://hdl.handle.net/2027%2Fhvd.hn3317?urlappend=%3Bseq=211">2027/hvd.hn3317</a><span class="reference-accessdate">. Retrieved <span class="nowrap">2024-07-02</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=HathiTrust&rft.atitle=Spectrum+analysis+in+its+application+to+terrestrial+substances+and+the+physical+constitution+of+the+heavenly+bodies+%3A+familiarly+explained+%2F+by+H.+Schellen+...&rft_id=info%3Ahdl%2F2027%2Fhvd.hn3317%3Furlappend%3D%253Bseq%3D211&rft_id=https%3A%2F%2Fhdl.handle.net%2F2027%2Fhvd.hn3317%3Furlappend%3D%253Bseq%3D211&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-Meadows-11"><span class="mw-cite-backlink">^ <a href="#cite_ref-Meadows_11-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Meadows_11-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMeadows1970" class="citation book cs1">Meadows, A. J. (Arthur Jack) (1970). <a rel="nofollow" class="external text" href="http://archive.org/details/earlysolarphysic0000mead"><i>Early solar physics</i></a>. Internet Archive. Oxford, New York, Pergamon Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-08-006653-0" title="Special:BookSources/978-0-08-006653-0"><bdi>978-0-08-006653-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Early+solar+physics&rft.pub=Oxford%2C+New+York%2C+Pergamon+Press&rft.date=1970&rft.isbn=978-0-08-006653-0&rft.aulast=Meadows&rft.aufirst=A.+J.+%28Arthur+Jack%29&rft_id=http%3A%2F%2Farchive.org%2Fdetails%2Fearlysolarphysic0000mead&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBaade1944" class="citation journal cs1">Baade, Walter (1944). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F144650">"The Resolution of Messier 32, NGC 205, and the central region of the Andromeda Nebula"</a>. <i>Astrophysical Journal</i>. <b>100</b>: <span class="nowrap">121–</span>146. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1944ApJ...100..137B">1944ApJ...100..137B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F144650">10.1086/144650</a></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astrophysical+Journal&rft.atitle=The+Resolution+of+Messier+32%2C+NGC+205%2C+and+the+central+region+of+the+Andromeda+Nebula&rft.volume=100&rft.pages=%3Cspan+class%3D%22nowrap%22%3E121-%3C%2Fspan%3E146&rft.date=1944&rft_id=info%3Adoi%2F10.1086%2F144650&rft_id=info%3Abibcode%2F1944ApJ...100..137B&rft.aulast=Baade&rft.aufirst=Walter&rft_id=https%3A%2F%2Fdoi.org%2F10.1086%252F144650&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRees1978" class="citation journal cs1">Rees, M.J. (1978). "Origin of pregalactic microwave background". <i>Nature</i>. <b>275</b> (5675): <span class="nowrap">35–</span>37. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1978Natur.275...35R">1978Natur.275...35R</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F275035a0">10.1038/275035a0</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:121250998">121250998</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Origin+of+pregalactic+microwave+background&rft.volume=275&rft.issue=5675&rft.pages=%3Cspan+class%3D%22nowrap%22%3E35-%3C%2Fspan%3E37&rft.date=1978&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A121250998%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1038%2F275035a0&rft_id=info%3Abibcode%2F1978Natur.275...35R&rft.aulast=Rees&rft.aufirst=M.J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWhiteRees1978" class="citation journal cs1">White, S.D.M.; Rees, M.J. (1978). <a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fmnras%2F183.3.341">"Core condensation in heavy halos - a two-stage theory for galaxy formation and clustering"</a>. <i>Monthly Notices of the Royal Astronomical Society</i>. <b>183</b> (3): <span class="nowrap">341–</span>358. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1978MNRAS.183..341W">1978MNRAS.183..341W</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fmnras%2F183.3.341">10.1093/mnras/183.3.341</a></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Monthly+Notices+of+the+Royal+Astronomical+Society&rft.atitle=Core+condensation+in+heavy+halos+-+a+two-stage+theory+for+galaxy+formation+and+clustering&rft.volume=183&rft.issue=3&rft.pages=%3Cspan+class%3D%22nowrap%22%3E341-%3C%2Fspan%3E358&rft.date=1978&rft_id=info%3Adoi%2F10.1093%2Fmnras%2F183.3.341&rft_id=info%3Abibcode%2F1978MNRAS.183..341W&rft.aulast=White&rft.aufirst=S.D.M.&rft.au=Rees%2C+M.J.&rft_id=https%3A%2F%2Fdoi.org%2F10.1093%252Fmnras%252F183.3.341&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPuget,_J.L.Heyvaerts,_J.1980" class="citation journal cs1">Puget, J.L.; Heyvaerts, J. (1980). "Population III stars and the shape of the cosmological black body radiation". <i>Astronomy and Astrophysics</i>. <b>83</b> (3): <span class="nowrap">L10 –</span> <span class="nowrap">L12</span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1980A&A....83L..10P">1980A&A....83L..10P</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astronomy+and+Astrophysics&rft.atitle=Population+III+stars+and+the+shape+of+the+cosmological+black+body+radiation&rft.volume=83&rft.issue=3&rft.pages=%3Cspan+class%3D%22nowrap%22%3EL10+-%3C%2Fspan%3E+%3Cspan+class%3D%22nowrap%22%3EL12%3C%2Fspan%3E&rft.date=1980&rft_id=info%3Abibcode%2F1980A%26A....83L..10P&rft.au=Puget%2C+J.L.&rft.au=Heyvaerts%2C+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-asplund-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-asplund_16-0">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAsplundGrevesseSauvalScott2009" class="citation journal cs1">Asplund, Martin; Grevesse, Nicolas; Sauval, A. Jacques; Scott, Pat (2009). "The chemical composition of the Sun". <i><a href="/wiki/Annual_Review_of_Astronomy_%26_Astrophysics" class="mw-redirect" title="Annual Review of Astronomy & Astrophysics">Annual Review of Astronomy & Astrophysics</a></i>. <b>47</b> (1): <span class="nowrap">481–</span>522. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/0909.0948">0909.0948</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2009ARA&A..47..481A">2009ARA&A..47..481A</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1146%2Fannurev.astro.46.060407.145222">10.1146/annurev.astro.46.060407.145222</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:17921922">17921922</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Annual+Review+of+Astronomy+%26+Astrophysics&rft.atitle=The+chemical+composition+of+the+Sun&rft.volume=47&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E481-%3C%2Fspan%3E522&rft.date=2009&rft_id=info%3Aarxiv%2F0909.0948&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A17921922%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1146%2Fannurev.astro.46.060407.145222&rft_id=info%3Abibcode%2F2009ARA%26A..47..481A&rft.aulast=Asplund&rft.aufirst=Martin&rft.au=Grevesse%2C+Nicolas&rft.au=Sauval%2C+A.+Jacques&rft.au=Scott%2C+Pat&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHinkelTimmesYoungPagano2014" class="citation journal cs1">Hinkel, Natalie; Timmes, Frank; Young, Patrick; Pagano, Michael; Turnbull, Maggie (September 2014). <a rel="nofollow" class="external text" href="https://iopscience.iop.org/article/10.1088/0004-6256/148/3/54">"Stellar abundances in the Solar neighborhood: <i>The Hypatia Catalog</i>"</a>. <i><a href="/wiki/Astronomical_Journal" class="mw-redirect" title="Astronomical Journal">Astronomical Journal</a></i>. <b>148</b> (3): 33. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/1405.6719">1405.6719</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2014AJ....148...54H">2014AJ....148...54H</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1088%2F0004-6256%2F148%2F3%2F54">10.1088/0004-6256/148/3/54</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:119221402">119221402</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astronomical+Journal&rft.atitle=Stellar+abundances+in+the+Solar+neighborhood%3A+The+Hypatia+Catalog&rft.volume=148&rft.issue=3&rft.pages=33&rft.date=2014-09&rft_id=info%3Aarxiv%2F1405.6719&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A119221402%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1088%2F0004-6256%2F148%2F3%2F54&rft_id=info%3Abibcode%2F2014AJ....148...54H&rft.aulast=Hinkel&rft.aufirst=Natalie&rft.au=Timmes%2C+Frank&rft.au=Young%2C+Patrick&rft.au=Pagano%2C+Michael&rft.au=Turnbull%2C+Maggie&rft_id=https%3A%2F%2Fiopscience.iop.org%2Farticle%2F10.1088%2F0004-6256%2F148%2F3%2F54&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-Matteucci2001-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-Matteucci2001_18-0">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMatteucci2001" class="citation book cs1">Matteucci, Francesca (2001). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=PT7O1nS7CksC&pg=PA7"><i>The Chemical Evolution of the Galaxy</i></a>. Astrophysics and Space Science Library. Vol. 253. Springer Science & Business Media. p. 7. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7923-6552-5" title="Special:BookSources/978-0-7923-6552-5"><bdi>978-0-7923-6552-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Chemical+Evolution+of+the+Galaxy&rft.series=Astrophysics+and+Space+Science+Library&rft.pages=7&rft.pub=Springer+Science+%26+Business+Media&rft.date=2001&rft.isbn=978-0-7923-6552-5&rft.aulast=Matteucci&rft.aufirst=Francesca&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DPT7O1nS7CksC%26pg%3DPA7&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-19">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFenna2002" class="citation book cs1">Fenna, Donald (2002). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=uBk9DAAAQBAJ&pg=PT92"><i>A Dictionary of Weights, Measures, and Units</i></a>. OUP Oxford. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780191078989" title="Special:BookSources/9780191078989"><bdi>9780191078989</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+Dictionary+of+Weights%2C+Measures%2C+and+Units&rft.pub=OUP+Oxford&rft.date=2002&rft.isbn=9780191078989&rft.aulast=Fenna&rft.aufirst=Donald&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DuBk9DAAAQBAJ%26pg%3DPT92&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-Martin-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-Martin_20-0">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMartin,_John_C." class="citation web cs1">Martin, John C. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20141009051221/https://edocs.uis.edu/jmart5/www/rrlyrae/metals.htm">"What we learn from a star's metal content"</a>. New analysis RR Lyrae kinematics in the solar neighborhood. <a href="/wiki/University_of_Illinois,_Springfield" class="mw-redirect" title="University of Illinois, Springfield">University of Illinois, Springfield</a>. Archived from <a rel="nofollow" class="external text" href="https://edocs.uis.edu/jmart5/www/rrlyrae/metals.htm">the original</a> on 2014-10-09<span class="reference-accessdate">. Retrieved <span class="nowrap">7 September</span> 2005</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=What+we+learn+from+a+star%27s+metal+content&rft.series=New+analysis+RR+Lyrae+kinematics+in+the+solar+neighborhood&rft.pub=University+of+Illinois%2C+Springfield&rft.au=Martin%2C+John+C.&rft_id=https%3A%2F%2Fedocs.uis.edu%2Fjmart5%2Fwww%2Frrlyrae%2Fmetals.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-AJ-20150604-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-AJ-20150604_21-0">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSobralMattheeDarvishSchaerer2015" class="citation journal cs1">Sobral, David; Matthee, Jorryt; Darvish, Behnam; Schaerer, Daniel; Mobasher, Bahram; Röttgering, Huub J.A.; et al. (4 June 2015). "Evidence for pop III-like stellar populations in the most luminous Lyman-α emitters at the epoch of re-ionisation: Spectroscopic confirmation". <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>808</b> (2): 139. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/1504.01734">1504.01734</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2015ApJ...808..139S">2015ApJ...808..139S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1088%2F0004-637x%2F808%2F2%2F139">10.1088/0004-637x/808/2/139</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:18471887">18471887</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=Evidence+for+pop+III-like+stellar+populations+in+the+most+luminous+Lyman-%CE%B1+emitters+at+the+epoch+of+re-ionisation%3A+Spectroscopic+confirmation&rft.volume=808&rft.issue=2&rft.pages=139&rft.date=2015-06-04&rft_id=info%3Aarxiv%2F1504.01734&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A18471887%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1088%2F0004-637x%2F808%2F2%2F139&rft_id=info%3Abibcode%2F2015ApJ...808..139S&rft.aulast=Sobral&rft.aufirst=David&rft.au=Matthee%2C+Jorryt&rft.au=Darvish%2C+Behnam&rft.au=Schaerer%2C+Daniel&rft.au=Mobasher%2C+Bahram&rft.au=R%C3%B6ttgering%2C+Huub+J.A.&rft.au=Santos%2C+S%C3%A9rgio&rft.au=Hemmati%2C+Shoubaneh&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-NYT-20150617-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-NYT-20150617_22-0">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFOverbye2015" class="citation news cs1"><a href="/wiki/Dennis_Overbye" title="Dennis Overbye">Overbye, Dennis</a> (17 June 2015). <a rel="nofollow" class="external text" href="https://www.nytimes.com/2015/06/18/science/space/astronomers-report-finding-earliest-stars-that-enriched-cosmos.html">"Astronomers report finding earliest stars that enriched the cosmos"</a>. <i><a href="/wiki/The_New_York_Times" title="The New York Times">The New York Times</a></i><span class="reference-accessdate">. Retrieved <span class="nowrap">17 June</span> 2015</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+New+York+Times&rft.atitle=Astronomers+report+finding+earliest+stars+that+enriched+the+cosmos&rft.date=2015-06-17&rft.aulast=Overbye&rft.aufirst=Dennis&rft_id=https%3A%2F%2Fwww.nytimes.com%2F2015%2F06%2F18%2Fscience%2Fspace%2Fastronomers-report-finding-earliest-stars-that-enriched-cosmos.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-23">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJohnsonMorgan1953" class="citation journal cs1">Johnson, H.L.; Morgan, W.W. (May 1953). "Fundamental stellar photometry for standards of spectral type on the revised system of the <i>Yerkes Spectral Atlas</i>". <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>117</b>: 313. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1953ApJ...117..313J">1953ApJ...117..313J</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F145697">10.1086/145697</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-637X">0004-637X</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=Fundamental+stellar+photometry+for+standards+of+spectral+type+on+the+revised+system+of+the+Yerkes+Spectral+Atlas&rft.volume=117&rft.pages=313&rft.date=1953-05&rft.issn=0004-637X&rft_id=info%3Adoi%2F10.1086%2F145697&rft_id=info%3Abibcode%2F1953ApJ...117..313J&rft.aulast=Johnson&rft.aufirst=H.L.&rft.au=Morgan%2C+W.W.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-24">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRoman1955" class="citation journal cs1">Roman, Nancy G. (December 1955). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F190021">"A catalogue of high-velocity stars"</a>. <i>The Astrophysical Journal Supplement Series</i>. <b>2</b>: 195. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1955ApJS....2..195R">1955ApJS....2..195R</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F190021">10.1086/190021</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0067-0049">0067-0049</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal+Supplement+Series&rft.atitle=A+catalogue+of+high-velocity+stars&rft.volume=2&rft.pages=195&rft.date=1955-12&rft.issn=0067-0049&rft_id=info%3Adoi%2F10.1086%2F190021&rft_id=info%3Abibcode%2F1955ApJS....2..195R&rft.aulast=Roman&rft.aufirst=Nancy+G.&rft_id=https%3A%2F%2Fdoi.org%2F10.1086%252F190021&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-25">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSandageEggen1959" class="citation journal cs1"><a href="/wiki/Allan_Sandage" title="Allan Sandage">Sandage, A.R.</a>; Eggen, O.J. (1959-06-01). <a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fmnras%2F119.3.278">"On the existence of subdwarfs in the (MBol, log Te)-diagram"</a>. <i><a href="/wiki/Monthly_Notices_of_the_Royal_Astronomical_Society" title="Monthly Notices of the Royal Astronomical Society">Monthly Notices of the Royal Astronomical Society</a></i>. <b>119</b> (3): <span class="nowrap">278–</span>296. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1959MNRAS.119..278S">1959MNRAS.119..278S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fmnras%2F119.3.278">10.1093/mnras/119.3.278</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0035-8711">0035-8711</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Monthly+Notices+of+the+Royal+Astronomical+Society&rft.atitle=On+the+existence+of+subdwarfs+in+the+%28MBol%2C+log+Te%29-diagram&rft.volume=119&rft.issue=3&rft.pages=%3Cspan+class%3D%22nowrap%22%3E278-%3C%2Fspan%3E296&rft.date=1959-06-01&rft.issn=0035-8711&rft_id=info%3Adoi%2F10.1093%2Fmnras%2F119.3.278&rft_id=info%3Abibcode%2F1959MNRAS.119..278S&rft.aulast=Sandage&rft.aufirst=A.R.&rft.au=Eggen%2C+O.J.&rft_id=https%3A%2F%2Fdoi.org%2F10.1093%252Fmnras%252F119.3.278&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-26">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWallersteinCarlson1960" class="citation journal cs1">Wallerstein, George; Carlson, Maurice (September 1960). "Letter to the Editor: On the ultraviolet excess in G dwarfs". <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>132</b>: 276. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1960ApJ...132..276W">1960ApJ...132..276W</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F146926">10.1086/146926</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-637X">0004-637X</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=Letter+to+the+Editor%3A+On+the+ultraviolet+excess+in+G+dwarfs&rft.volume=132&rft.pages=276&rft.date=1960-09&rft.issn=0004-637X&rft_id=info%3Adoi%2F10.1086%2F146926&rft_id=info%3Abibcode%2F1960ApJ...132..276W&rft.aulast=Wallerstein&rft.aufirst=George&rft.au=Carlson%2C+Maurice&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-Wildey-Burbidge-etal-1962-27"><span class="mw-cite-backlink">^ <a href="#cite_ref-Wildey-Burbidge-etal-1962_27-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Wildey-Burbidge-etal-1962_27-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWildeyBurbidgeSandageBurbidge1962" class="citation journal cs1">Wildey, R.L.; Burbidge, E.M.; <a href="/wiki/Allan_Sandage" title="Allan Sandage">Sandage, A.R.</a>; Burbidge, G.R. (January 1962). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F147251">"On the effect of Fraunhofer lines on u, b, V measurements"</a>. <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>135</b>: 94. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1962ApJ...135...94W">1962ApJ...135...94W</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F147251">10.1086/147251</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-637X">0004-637X</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=On+the+effect+of+Fraunhofer+lines+on+u%2C+b%2C+V+measurements&rft.volume=135&rft.pages=94&rft.date=1962-01&rft.issn=0004-637X&rft_id=info%3Adoi%2F10.1086%2F147251&rft_id=info%3Abibcode%2F1962ApJ...135...94W&rft.aulast=Wildey&rft.aufirst=R.L.&rft.au=Burbidge%2C+E.M.&rft.au=Sandage%2C+A.R.&rft.au=Burbidge%2C+G.R.&rft_id=https%3A%2F%2Fdoi.org%2F10.1086%252F147251&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-28"><span class="mw-cite-backlink"><b><a href="#cite_ref-28">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSchwarzschildSearleHoward1955" class="citation journal cs1">Schwarzschild, M.; Searle, L.; Howard, R. (September 1955). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F146094">"On the colors of subdwarfs"</a>. <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>122</b>: 353. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1955ApJ...122..353S">1955ApJ...122..353S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F146094">10.1086/146094</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-637X">0004-637X</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=On+the+colors+of+subdwarfs&rft.volume=122&rft.pages=353&rft.date=1955-09&rft.issn=0004-637X&rft_id=info%3Adoi%2F10.1086%2F146094&rft_id=info%3Abibcode%2F1955ApJ...122..353S&rft.aulast=Schwarzschild&rft.aufirst=M.&rft.au=Searle%2C+L.&rft.au=Howard%2C+R.&rft_id=https%3A%2F%2Fdoi.org%2F10.1086%252F146094&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-29"><span class="mw-cite-backlink"><b><a href="#cite_ref-29">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCameron1985" class="citation journal cs1">Cameron, L. M. (June 1985). "Metallicities and distances of galactic clusters as determined from UBV data – Part Three – Ages and abundance gradients of open clusters". <i><a href="/wiki/Astronomy_and_Astrophysics" class="mw-redirect" title="Astronomy and Astrophysics">Astronomy and Astrophysics</a></i>. <b>147</b>: 47. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1985A&A...147...47C">1985A&A...147...47C</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-6361">0004-6361</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astronomy+and+Astrophysics&rft.atitle=Metallicities+and+distances+of+galactic+clusters+as+determined+from+UBV+data+%E2%80%93+Part+Three+%E2%80%93+Ages+and+abundance+gradients+of+open+clusters&rft.volume=147&rft.pages=47&rft.date=1985-06&rft.issn=0004-6361&rft_id=info%3Abibcode%2F1985A%26A...147...47C&rft.aulast=Cameron&rft.aufirst=L.+M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-30"><span class="mw-cite-backlink"><b><a href="#cite_ref-30">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSandage1969" class="citation journal cs1"><a href="/wiki/Allan_Sandage" title="Allan Sandage">Sandage, A.R.</a> (December 1969). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F150271">"New subdwarfs. II. Radial velocities, photometry, and preliminary space motions for 112 stars with large proper motion"</a>. <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>158</b>: 1115. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1969ApJ...158.1115S">1969ApJ...158.1115S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F150271">10.1086/150271</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-637X">0004-637X</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=New+subdwarfs.+II.+Radial+velocities%2C+photometry%2C+and+preliminary+space+motions+for+112+stars+with+large+proper+motion&rft.volume=158&rft.pages=1115&rft.date=1969-12&rft.issn=0004-637X&rft_id=info%3Adoi%2F10.1086%2F150271&rft_id=info%3Abibcode%2F1969ApJ...158.1115S&rft.aulast=Sandage&rft.aufirst=A.R.&rft_id=https%3A%2F%2Fdoi.org%2F10.1086%252F150271&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-31"><span class="mw-cite-backlink"><b><a href="#cite_ref-31">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCarney1979" class="citation journal cs1">Carney, B.W. (October 1979). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F157383">"Subdwarf ultraviolet excesses and metal abundances"</a>. <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>233</b>: 211. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1979ApJ...233..211C">1979ApJ...233..211C</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F157383">10.1086/157383</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-637X">0004-637X</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=Subdwarf+ultraviolet+excesses+and+metal+abundances&rft.volume=233&rft.pages=211&rft.date=1979-10&rft.issn=0004-637X&rft_id=info%3Adoi%2F10.1086%2F157383&rft_id=info%3Abibcode%2F1979ApJ...233..211C&rft.aulast=Carney&rft.aufirst=B.W.&rft_id=https%3A%2F%2Fdoi.org%2F10.1086%252F157383&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-32"><span class="mw-cite-backlink"><b><a href="#cite_ref-32">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLairdCarneyLatham1988" class="citation journal cs1">Laird, John B.; Carney, Bruce W.; Latham, David W. (June 1988). "A survey of proper-motion stars. III - Reddenings, distances, and metallicities". <i><a href="/wiki/The_Astronomical_Journal" title="The Astronomical Journal">The Astronomical Journal</a></i>. <b>95</b>: 1843. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1988AJ.....95.1843L">1988AJ.....95.1843L</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F114782">10.1086/114782</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-6256">0004-6256</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astronomical+Journal&rft.atitle=A+survey+of+proper-motion+stars.+III+-+Reddenings%2C+distances%2C+and+metallicities&rft.volume=95&rft.pages=1843&rft.date=1988-06&rft.issn=0004-6256&rft_id=info%3Adoi%2F10.1086%2F114782&rft_id=info%3Abibcode%2F1988AJ.....95.1843L&rft.aulast=Laird&rft.aufirst=John+B.&rft.au=Carney%2C+Bruce+W.&rft.au=Latham%2C+David+W.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-33"><span class="mw-cite-backlink"><b><a href="#cite_ref-33">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStrömgren1963" class="citation book cs1">Strömgren, Bengt (1963). "Quantitative classification methods". In Strand, Kaj Aage (ed.). <i>Basic Astronomical Data: Stars and stellar systems</i> (original (re-issued 1968) ed.). Chicago, IL: University of Chicago Press. p. 123. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1963bad..book..123S">1963bad..book..123S</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Quantitative+classification+methods&rft.btitle=Basic+Astronomical+Data%3A+Stars+and+stellar+systems&rft.place=Chicago%2C+IL&rft.pages=123&rft.edition=original+%28re-issued+1968%29&rft.pub=University+of+Chicago+Press&rft.date=1963&rft_id=info%3Abibcode%2F1963bad..book..123S&rft.aulast=Str%C3%B6mgren&rft.aufirst=Bengt&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span> <ul><li>1980 reprint edition: <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://www.worldcat.org/oclc/7047642">7047642</a>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-2264-5964-0" title="Special:BookSources/0-2264-5964-0">0-2264-5964-0</a></li> <li>1988 reprint edition: <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-2-2645-9640-6" title="Special:BookSources/978-2-2645-9640-6">978-2-2645-9640-6</a></li></ul> </span></li> <li id="cite_note-34"><span class="mw-cite-backlink"><b><a href="#cite_ref-34">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCrawford1966" class="citation journal cs1">Crawford, L.D. (1966). "Photo-electric H-beta and U V B Y photometry". <i>Spectral Classification and Multicolour Photometry</i>. <b>24</b>: 170. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1966IAUS...24..170C">1966IAUS...24..170C</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Spectral+Classification+and+Multicolour+Photometry&rft.atitle=Photo-electric+H-beta+and+U+V+B+Y+photometry&rft.volume=24&rft.pages=170&rft.date=1966&rft_id=info%3Abibcode%2F1966IAUS...24..170C&rft.aulast=Crawford&rft.aufirst=L.D.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-35"><span class="mw-cite-backlink"><b><a href="#cite_ref-35">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCramerMaeder1979" class="citation journal cs1">Cramer, N.; Maeder, A. (October 1979). "Luminosity and <span class="texhtml mvar" style="font-style:italic;">T</span><sub>eff</sub> determinations for B-type stars". <i>Astronomy and Astrophysics</i>. <b>78</b>: 305. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1979A&A....78..305C">1979A&A....78..305C</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-6361">0004-6361</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astronomy+and+Astrophysics&rft.atitle=Luminosity+and+%3Cspan+class%3D%22texhtml+mvar%22+style%3D%22font-style%3Aitalic%3B%22%3ET%3C%2Fspan%3E%3Csub%3Eeff%3C%2Fsub%3E+determinations+for+B-type+stars&rft.volume=78&rft.pages=305&rft.date=1979-10&rft.issn=0004-6361&rft_id=info%3Abibcode%2F1979A%26A....78..305C&rft.aulast=Cramer&rft.aufirst=N.&rft.au=Maeder%2C+A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-36"><span class="mw-cite-backlink"><b><a href="#cite_ref-36">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKobiNorth1990" class="citation journal cs1">Kobi, D.; North, P. (November 1990). "A new calibration of the Geneva photometry in terms of Te, log g, (Fe/H) and mass for main sequence A4 to G5 stars". <i>Astronomy and Astrophysics Supplement Series</i>. <b>85</b>: 999. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1990A&AS...85..999K">1990A&AS...85..999K</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0365-0138">0365-0138</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astronomy+and+Astrophysics+Supplement+Series&rft.atitle=A+new+calibration+of+the+Geneva+photometry+in+terms+of+Te%2C+log+g%2C+%28Fe%2FH%29+and+mass+for+main+sequence+A4+to+G5+stars&rft.volume=85&rft.pages=999&rft.date=1990-11&rft.issn=0365-0138&rft_id=info%3Abibcode%2F1990A%26AS...85..999K&rft.aulast=Kobi&rft.aufirst=D.&rft.au=North%2C+P.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-37"><span class="mw-cite-backlink"><b><a href="#cite_ref-37">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGeisler1986" class="citation journal cs1">Geisler, D. (1986). <a rel="nofollow" class="external text" href="http://stacks.iop.org/1538-3873/98/i=606/a=762">"The empirical abundance calibrations for Washington photometry of population II giants"</a>. <i>Publications of the Astronomical Society of the Pacific</i>. <b>98</b> (606): 762. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1986PASP...98..762G">1986PASP...98..762G</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F131822">10.1086/131822</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1538-3873">1538-3873</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Publications+of+the+Astronomical+Society+of+the+Pacific&rft.atitle=The+empirical+abundance+calibrations+for+Washington+photometry+of+population+II+giants&rft.volume=98&rft.issue=606&rft.pages=762&rft.date=1986&rft.issn=1538-3873&rft_id=info%3Adoi%2F10.1086%2F131822&rft_id=info%3Abibcode%2F1986PASP...98..762G&rft.aulast=Geisler&rft.aufirst=D.&rft_id=http%3A%2F%2Fstacks.iop.org%2F1538-3873%2F98%2Fi%3D606%2Fa%3D762&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-38"><span class="mw-cite-backlink"><b><a href="#cite_ref-38">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGeislerClariaMinniti1991" class="citation journal cs1">Geisler, Doug; Claria, Juan J.; Minniti, Dante (November 1991). "An improved metal abundance calibration for the Washington system". <i>The Astronomical Journal</i>. <b>102</b>: 1836. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1991AJ....102.1836G">1991AJ....102.1836G</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F116008">10.1086/116008</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-6256">0004-6256</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astronomical+Journal&rft.atitle=An+improved+metal+abundance+calibration+for+the+Washington+system&rft.volume=102&rft.pages=1836&rft.date=1991-11&rft.issn=0004-6256&rft_id=info%3Adoi%2F10.1086%2F116008&rft_id=info%3Abibcode%2F1991AJ....102.1836G&rft.aulast=Geisler&rft.aufirst=Doug&rft.au=Claria%2C+Juan+J.&rft.au=Minniti%2C+Dante&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-39"><span class="mw-cite-backlink"><b><a href="#cite_ref-39">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFClariaPiattiLapasset1994" class="citation journal cs1">Claria, Juan J.; Piatti, Andres E.; Lapasset, Emilio (May 1994). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F133398">"A revised effective-temperature calibration for the DDO photometric system"</a>. <i>Publications of the Astronomical Society of the Pacific</i>. <b>106</b>: 436. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1994PASP..106..436C">1994PASP..106..436C</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F133398">10.1086/133398</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-6280">0004-6280</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Publications+of+the+Astronomical+Society+of+the+Pacific&rft.atitle=A+revised+effective-temperature+calibration+for+the+DDO+photometric+system&rft.volume=106&rft.pages=436&rft.date=1994-05&rft.issn=0004-6280&rft_id=info%3Adoi%2F10.1086%2F133398&rft_id=info%3Abibcode%2F1994PASP..106..436C&rft.aulast=Claria&rft.aufirst=Juan+J.&rft.au=Piatti%2C+Andres+E.&rft.au=Lapasset%2C+Emilio&rft_id=https%3A%2F%2Fdoi.org%2F10.1086%252F133398&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-40"><span class="mw-cite-backlink"><b><a href="#cite_ref-40">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJames1975" class="citation journal cs1">James, K.A. (May 1975). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F190339">"Cyanogen strengths, luminosities, and kinematics of K giant stars"</a>. <i>The Astrophysical Journal Supplement Series</i>. <b>29</b>: 161. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1975ApJS...29..161J">1975ApJS...29..161J</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F190339">10.1086/190339</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0067-0049">0067-0049</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal+Supplement+Series&rft.atitle=Cyanogen+strengths%2C+luminosities%2C+and+kinematics+of+K+giant+stars&rft.volume=29&rft.pages=161&rft.date=1975-05&rft.issn=0067-0049&rft_id=info%3Adoi%2F10.1086%2F190339&rft_id=info%3Abibcode%2F1975ApJS...29..161J&rft.aulast=James&rft.aufirst=K.A.&rft_id=https%3A%2F%2Fdoi.org%2F10.1086%252F190339&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-41"><span class="mw-cite-backlink"><b><a href="#cite_ref-41">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWang" class="citation web cs1">Wang, Ji. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170713073323/http://www.astro.caltech.edu/~jwang/Project4.html">"Planet-metallicity correlation - the rich get richer"</a>. <a href="/wiki/Caltech" class="mw-redirect" title="Caltech">Caltech</a>. Archived from <a rel="nofollow" class="external text" href="http://www.astro.caltech.edu/~jwang/Project4.html">the original</a> on 2017-07-13<span class="reference-accessdate">. Retrieved <span class="nowrap">2016-09-28</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Planet-metallicity+correlation+-+the+rich+get+richer&rft.pub=Caltech&rft.aulast=Wang&rft.aufirst=Ji&rft_id=http%3A%2F%2Fwww.astro.caltech.edu%2F~jwang%2FProject4.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-42"><span class="mw-cite-backlink"><b><a href="#cite_ref-42">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFischerValenti2005" class="citation journal cs1">Fischer, Debra A.; Valenti, Jeff (2005). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F428383">"The planet-metallicity correlation"</a>. <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>622</b> (2): 1102. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2005ApJ...622.1102F">2005ApJ...622.1102F</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F428383">10.1086/428383</a></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=The+planet-metallicity+correlation&rft.volume=622&rft.issue=2&rft.pages=1102&rft.date=2005&rft_id=info%3Adoi%2F10.1086%2F428383&rft_id=info%3Abibcode%2F2005ApJ...622.1102F&rft.aulast=Fischer&rft.aufirst=Debra+A.&rft.au=Valenti%2C+Jeff&rft_id=https%3A%2F%2Fdoi.org%2F10.1086%252F428383&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-43"><span class="mw-cite-backlink"><b><a href="#cite_ref-43">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWangFischer2013" class="citation journal cs1">Wang, Ji; Fischer, Debra A. (2013). "Revealing a universal planet-metallicity correlation for planets of different sizes around Solar-type stars". <i><a href="/wiki/The_Astronomical_Journal" title="The Astronomical Journal">The Astronomical Journal</a></i>. <b>149</b> (1): 14. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/1310.7830">1310.7830</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2015AJ....149...14W">2015AJ....149...14W</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1088%2F0004-6256%2F149%2F1%2F14">10.1088/0004-6256/149/1/14</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:118415186">118415186</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astronomical+Journal&rft.atitle=Revealing+a+universal+planet-metallicity+correlation+for+planets+of+different+sizes+around+Solar-type+stars&rft.volume=149&rft.issue=1&rft.pages=14&rft.date=2013&rft_id=info%3Aarxiv%2F1310.7830&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A118415186%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1088%2F0004-6256%2F149%2F1%2F14&rft_id=info%3Abibcode%2F2015AJ....149...14W&rft.aulast=Wang&rft.aufirst=Ji&rft.au=Fischer%2C+Debra+A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-44"><span class="mw-cite-backlink"><b><a href="#cite_ref-44">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSanders,_Ray2012" class="citation magazine cs1">Sanders, Ray (9 April 2012). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20210507132606/https://www.astrobio.net/news-exclusive/when-stellar-metallicity-sparks-planet-formation/">"When stellar metallicity sparks planet formation"</a>. <i>Astrobiology Magazine</i>. Archived from <a rel="nofollow" class="external text" href="http://www.astrobio.net/news-exclusive/when-stellar-metallicity-sparks-planet-formation/">the original</a> on 2021-05-07.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astrobiology+Magazine&rft.atitle=When+stellar+metallicity+sparks+planet+formation&rft.date=2012-04-09&rft.au=Sanders%2C+Ray&rft_id=http%3A%2F%2Fwww.astrobio.net%2Fnews-exclusive%2Fwhen-stellar-metallicity-sparks-planet-formation%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-45"><span class="mw-cite-backlink"><b><a href="#cite_ref-45">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHill,_VanessaFrançois,_PatrickPrimas,_Francesca" class="citation conference cs1">Hill, Vanessa; François, Patrick; <a href="/wiki/Francesca_Primas" title="Francesca Primas">Primas, Francesca</a> (eds.). "The G star problem". <i>From Lithium to Uranium: Elemental tracers of early cosmic evolution</i>. <a href="/wiki/International_Astronomical_Union" title="International Astronomical Union">IAU</a> Symposium 228. Proceedings of the <a href="/wiki/International_Astronomical_Union" title="International Astronomical Union">International Astronomical Union</a> Symposia and Colloquia. Vol. 228. pp. <span class="nowrap">509–</span>511.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=conference&rft.atitle=The+G+star+problem&rft.btitle=From+Lithium+to+Uranium%3A+Elemental+tracers+of+early+cosmic+evolution&rft.series=Proceedings+of+the+International+Astronomical+Union+Symposia+and+Colloquia&rft.pages=%3Cspan+class%3D%22nowrap%22%3E509-%3C%2Fspan%3E511&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span> <sup class="noprint Inline-Template" style="white-space:nowrap;">[<i><a href="/wiki/Template:Harvard_citation_documentation#Wikilink_to_citation_does_not_work" title="Template:Harvard citation documentation"><span title="Template:Harvard citation documentation#Wikilink to citation does not work (2023-03-20)">citation not found</span></a></i>]</sup> <dl><dd>Missing article's page numbers are imbedded in:</dd></dl> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFArimoto,_N.2005" class="citation conference cs1">Arimoto, N. (23–27 May 2005). "Linking the halo to its surroundings". In Hill, Vanessa; François, Patrick; <a href="/wiki/Francesca_Primas" title="Francesca Primas">Primas, Francesca</a> (eds.). <i>From Lithium to Uranium: Elemental tracers of early cosmic evolution</i>. <a href="/wiki/International_Astronomical_Union" title="International Astronomical Union">IAU</a> Symposium 228. Proceedings of the <a href="/wiki/International_Astronomical_Union" title="International Astronomical Union">International Astronomical Union</a> Symposia and Colloquia. Vol. 228. Paris, France: <a href="/wiki/International_Astronomical_Union" title="International Astronomical Union">IAU</a> / Cambridge University Press (published February 2006). pp. <span class="nowrap">503–</span>512. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2005IAUS..228..503A">2005IAUS..228..503A</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1017%2FS1743921305006344">10.1017/S1743921305006344</a></span>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-52185199-2" title="Special:BookSources/978-0-52185199-2"><bdi>978-0-52185199-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=conference&rft.atitle=Linking+the+halo+to+its+surroundings&rft.btitle=From+Lithium+to+Uranium%3A+Elemental+tracers+of+early+cosmic+evolution&rft.place=Paris%2C+France&rft.series=Proceedings+of+the+International+Astronomical+Union+Symposia+and+Colloquia&rft.pages=%3Cspan+class%3D%22nowrap%22%3E503-%3C%2Fspan%3E512&rft.pub=IAU+%2F+Cambridge+University+Press&rft.date=2005-05-23%2F2005-05-27&rft_id=info%3Adoi%2F10.1017%2FS1743921305006344&rft_id=info%3Abibcode%2F2005IAUS..228..503A&rft.isbn=978-0-52185199-2&rft.au=Arimoto%2C+N.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-46"><span class="mw-cite-backlink"><b><a href="#cite_ref-46">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKewleyDopita2002" class="citation journal cs1">Kewley, L.J.; Dopita, M.A. (September 2002). "Using strong lines to estimate abundances in extragalactic H<sup>II</sup> regions and starburst galaxies". <i>The Astrophysical Journal Supplement Series</i>. <b>142</b> (1): <span class="nowrap">35–</span>52. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/astro-ph/0206495">astro-ph/0206495</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2002ApJS..142...35K">2002ApJS..142...35K</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F341326">10.1086/341326</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0067-0049">0067-0049</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:16655590">16655590</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal+Supplement+Series&rft.atitle=Using+strong+lines+to+estimate+abundances+in+extragalactic+H%3Csup%3EII%3C%2Fsup%3E+regions+and+starburst+galaxies&rft.volume=142&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E35-%3C%2Fspan%3E52&rft.date=2002-09&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A16655590%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2002ApJS..142...35K&rft_id=info%3Aarxiv%2Fastro-ph%2F0206495&rft.issn=0067-0049&rft_id=info%3Adoi%2F10.1086%2F341326&rft.aulast=Kewley&rft.aufirst=L.J.&rft.au=Dopita%2C+M.A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-47"><span class="mw-cite-backlink"><b><a href="#cite_ref-47">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNagaoMaiolinoMarconi2006" class="citation journal cs1">Nagao, T.; Maiolino, R.; Marconi, A. (2006-09-12). "Gas metallicity diagnostics in star-forming galaxies". <i><a href="/wiki/Astronomy_%26_Astrophysics" title="Astronomy & Astrophysics">Astronomy & Astrophysics</a></i>. <b>459</b> (1): <span class="nowrap">85–</span>101. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/astro-ph/0603580">astro-ph/0603580</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2006A&A...459...85N">2006A&A...459...85N</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1051%2F0004-6361%3A20065216">10.1051/0004-6361:20065216</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-6361">0004-6361</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:16220272">16220272</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astronomy+%26+Astrophysics&rft.atitle=Gas+metallicity+diagnostics+in+star-forming+galaxies&rft.volume=459&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E85-%3C%2Fspan%3E101&rft.date=2006-09-12&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A16220272%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2006A%26A...459...85N&rft_id=info%3Aarxiv%2Fastro-ph%2F0603580&rft.issn=0004-6361&rft_id=info%3Adoi%2F10.1051%2F0004-6361%3A20065216&rft.aulast=Nagao&rft.aufirst=T.&rft.au=Maiolino%2C+R.&rft.au=Marconi%2C+A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-48"><span class="mw-cite-backlink"><b><a href="#cite_ref-48">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPeimbert1967" class="citation journal cs1">Peimbert, Manuel (December 1967). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F149385">"Temperature determinations of H<sup>II</sup> regions"</a>. <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>150</b>: 825. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1967ApJ...150..825P">1967ApJ...150..825P</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F149385">10.1086/149385</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-637X">0004-637X</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=Temperature+determinations+of+H%3Csup%3EII%3C%2Fsup%3E+regions&rft.volume=150&rft.pages=825&rft.date=1967-12&rft.issn=0004-637X&rft_id=info%3Adoi%2F10.1086%2F149385&rft_id=info%3Abibcode%2F1967ApJ...150..825P&rft.aulast=Peimbert&rft.aufirst=Manuel&rft_id=https%3A%2F%2Fdoi.org%2F10.1086%252F149385&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-49"><span class="mw-cite-backlink"><b><a href="#cite_ref-49">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPagel1986" class="citation journal cs1">Pagel, B.E.J. (1986). <a rel="nofollow" class="external text" href="http://stacks.iop.org/1538-3873/98/i=608/a=1009">"Nebulae and abundances in galaxies"</a>. <i><a href="/wiki/Publications_of_the_Astronomical_Society_of_the_Pacific" title="Publications of the Astronomical Society of the Pacific">Publications of the Astronomical Society of the Pacific</a></i>. <b>98</b> (608): 1009. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1986PASP...98.1009P">1986PASP...98.1009P</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F131863">10.1086/131863</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1538-3873">1538-3873</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:120467036">120467036</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Publications+of+the+Astronomical+Society+of+the+Pacific&rft.atitle=Nebulae+and+abundances+in+galaxies&rft.volume=98&rft.issue=608&rft.pages=1009&rft.date=1986&rft_id=info%3Adoi%2F10.1086%2F131863&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A120467036%23id-name%3DS2CID&rft.issn=1538-3873&rft_id=info%3Abibcode%2F1986PASP...98.1009P&rft.aulast=Pagel&rft.aufirst=B.E.J.&rft_id=http%3A%2F%2Fstacks.iop.org%2F1538-3873%2F98%2Fi%3D608%2Fa%3D1009&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-50"><span class="mw-cite-backlink"><b><a href="#cite_ref-50">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHenryWorthey1999" class="citation journal cs1">Henry, R.B.C.; Worthey, Guy (August 1999). "The distribution of heavy elements in spiral and elliptical galaxies". <i><a href="/wiki/Publications_of_the_Astronomical_Society_of_the_Pacific" title="Publications of the Astronomical Society of the Pacific">Publications of the Astronomical Society of the Pacific</a></i>. <b>111</b> (762): <span class="nowrap">919–</span>945. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/astro-ph/9904017">astro-ph/9904017</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1999PASP..111..919H">1999PASP..111..919H</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F316403">10.1086/316403</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-6280">0004-6280</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:17106463">17106463</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Publications+of+the+Astronomical+Society+of+the+Pacific&rft.atitle=The+distribution+of+heavy+elements+in+spiral+and+elliptical+galaxies&rft.volume=111&rft.issue=762&rft.pages=%3Cspan+class%3D%22nowrap%22%3E919-%3C%2Fspan%3E945&rft.date=1999-08&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A17106463%23id-name%3DS2CID&rft_id=info%3Abibcode%2F1999PASP..111..919H&rft_id=info%3Aarxiv%2Fastro-ph%2F9904017&rft.issn=0004-6280&rft_id=info%3Adoi%2F10.1086%2F316403&rft.aulast=Henry&rft.aufirst=R.B.C.&rft.au=Worthey%2C+Guy&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-51"><span class="mw-cite-backlink"><b><a href="#cite_ref-51">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKobulnickyKennicuttPizagno1999" class="citation journal cs1">Kobulnicky, Henry A.; Kennicutt, Robert C. Jr.; Pizagno, James L. (April 1999). "On measuring nebular chemical abundances in distant galaxies using global emission-line spectra". <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>514</b> (2): <span class="nowrap">544–</span>557. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/astro-ph/9811006">astro-ph/9811006</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1999ApJ...514..544K">1999ApJ...514..544K</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F306987">10.1086/306987</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-637X">0004-637X</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:14643540">14643540</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=On+measuring+nebular+chemical+abundances+in+distant+galaxies+using+global+emission-line+spectra&rft.volume=514&rft.issue=2&rft.pages=%3Cspan+class%3D%22nowrap%22%3E544-%3C%2Fspan%3E557&rft.date=1999-04&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A14643540%23id-name%3DS2CID&rft_id=info%3Abibcode%2F1999ApJ...514..544K&rft_id=info%3Aarxiv%2Fastro-ph%2F9811006&rft.issn=0004-637X&rft_id=info%3Adoi%2F10.1086%2F306987&rft.aulast=Kobulnicky&rft.aufirst=Henry+A.&rft.au=Kennicutt%2C+Robert+C.+Jr.&rft.au=Pizagno%2C+James+L.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-Grazyna-2004-Esteban-etal-52"><span class="mw-cite-backlink">^ <a href="#cite_ref-Grazyna-2004-Esteban-etal_52-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Grazyna-2004-Esteban-etal_52-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGrazyna2004" class="citation book cs1">Grazyna, Stasinska (2004). "Abundance determinations in H<sup>II</sup> regions and planetary nebulae". In Esteban, C.; Garcia Lopez, R.J.; Herrero, A.; Sanchez, F. (eds.). <i>Cosmochemistry: The melting pot of the elements</i>. Cambridge Contemporary Astrophysics. Cambridge University Press. pp. <span class="nowrap">115–</span>170. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/astro-ph/0207500">astro-ph/0207500</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2002astro.ph..7500S">2002astro.ph..7500S</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Abundance+determinations+in+H%3Csup%3EII%3C%2Fsup%3E+regions+and+planetary+nebulae&rft.btitle=Cosmochemistry%3A+The+melting+pot+of+the+elements&rft.series=Cambridge+Contemporary+Astrophysics&rft.pages=%3Cspan+class%3D%22nowrap%22%3E115-%3C%2Fspan%3E170&rft.pub=Cambridge+University+Press&rft.date=2004&rft_id=info%3Aarxiv%2Fastro-ph%2F0207500&rft_id=info%3Abibcode%2F2002astro.ph..7500S&rft.aulast=Grazyna&rft.aufirst=Stasinska&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-53"><span class="mw-cite-backlink"><b><a href="#cite_ref-53">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPeimbertPeimbertRuiz2005" class="citation journal cs1">Peimbert, Antonio; Peimbert, Manuel; Ruiz, Maria Teresa (December 2005). "Chemical composition of two H<sup>II</sup> regions in NGC 6822 based on VLT spectroscopy". <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>634</b> (2): <span class="nowrap">1056–</span>1066. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/astro-ph/0507084">astro-ph/0507084</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2005ApJ...634.1056P">2005ApJ...634.1056P</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F444557">10.1086/444557</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-637X">0004-637X</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:17086551">17086551</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=Chemical+composition+of+two+H%3Csup%3EII%3C%2Fsup%3E+regions+in+NGC+6822+based+on+VLT+spectroscopy&rft.volume=634&rft.issue=2&rft.pages=%3Cspan+class%3D%22nowrap%22%3E1056-%3C%2Fspan%3E1066&rft.date=2005-12&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A17086551%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2005ApJ...634.1056P&rft_id=info%3Aarxiv%2Fastro-ph%2F0507084&rft.issn=0004-637X&rft_id=info%3Adoi%2F10.1086%2F444557&rft.aulast=Peimbert&rft.aufirst=Antonio&rft.au=Peimbert%2C+Manuel&rft.au=Ruiz%2C+Maria+Teresa&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-54"><span class="mw-cite-backlink"><b><a href="#cite_ref-54">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPagelEdmundsBlackwellChun1979" class="citation journal cs1">Pagel, B.E.J.; Edmunds, M.G.; Blackwell, D.E.; Chun, M.S.; Smith, G. (1979-11-01). <a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fmnras%2F189.1.95">"On the composition of H<sup>II</sup> regions in southern galaxies – I. NGC 300 and 1365"</a>. <i><a href="/wiki/Monthly_Notices_of_the_Royal_Astronomical_Society" title="Monthly Notices of the Royal Astronomical Society">Monthly Notices of the Royal Astronomical Society</a></i>. <b>189</b> (1): <span class="nowrap">95–</span>113. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1979MNRAS.189...95P">1979MNRAS.189...95P</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fmnras%2F189.1.95">10.1093/mnras/189.1.95</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0035-8711">0035-8711</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Monthly+Notices+of+the+Royal+Astronomical+Society&rft.atitle=On+the+composition+of+H%3Csup%3EII%3C%2Fsup%3E+regions+in+southern+galaxies+%E2%80%93+I.+NGC+300+and+1365&rft.volume=189&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E95-%3C%2Fspan%3E113&rft.date=1979-11-01&rft.issn=0035-8711&rft_id=info%3Adoi%2F10.1093%2Fmnras%2F189.1.95&rft_id=info%3Abibcode%2F1979MNRAS.189...95P&rft.aulast=Pagel&rft.aufirst=B.E.J.&rft.au=Edmunds%2C+M.G.&rft.au=Blackwell%2C+D.E.&rft.au=Chun%2C+M.S.&rft.au=Smith%2C+G.&rft_id=https%3A%2F%2Fdoi.org%2F10.1093%252Fmnras%252F189.1.95&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-55"><span class="mw-cite-backlink"><b><a href="#cite_ref-55">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDopitaEvans1986" class="citation journal cs1">Dopita, M.A.; Evans, I.N. (August 1986). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F164432">"Theoretical models for H<sup>II</sup> regions. II - The extragalactic H<sup>II</sup> region abundance sequence"</a>. <i>The Astrophysical Journal</i>. <b>307</b>: 431. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1986ApJ...307..431D">1986ApJ...307..431D</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F164432">10.1086/164432</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-637X">0004-637X</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=Theoretical+models+for+H%3Csup%3EII%3C%2Fsup%3E+regions.+II+-+The+extragalactic+H%3Csup%3EII%3C%2Fsup%3E+region+abundance+sequence&rft.volume=307&rft.pages=431&rft.date=1986-08&rft.issn=0004-637X&rft_id=info%3Adoi%2F10.1086%2F164432&rft_id=info%3Abibcode%2F1986ApJ...307..431D&rft.aulast=Dopita&rft.aufirst=M.A.&rft.au=Evans%2C+I.N.&rft_id=https%3A%2F%2Fdoi.org%2F10.1086%252F164432&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-56"><span class="mw-cite-backlink"><b><a href="#cite_ref-56">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMcGaugh1991" class="citation journal cs1">McGaugh, Stacy S. (October 1991). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F170569">"H<sup>II</sup> region abundances - Model oxygen line ratios"</a>. <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>380</b>: 140. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1991ApJ...380..140M">1991ApJ...380..140M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F170569">10.1086/170569</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-637X">0004-637X</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=H%3Csup%3EII%3C%2Fsup%3E+region+abundances+-+Model+oxygen+line+ratios&rft.volume=380&rft.pages=140&rft.date=1991-10&rft.issn=0004-637X&rft_id=info%3Adoi%2F10.1086%2F170569&rft_id=info%3Abibcode%2F1991ApJ...380..140M&rft.aulast=McGaugh&rft.aufirst=Stacy+S.&rft_id=https%3A%2F%2Fdoi.org%2F10.1086%252F170569&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-57"><span class="mw-cite-backlink"><b><a href="#cite_ref-57">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPilyugin2001" class="citation journal cs1">Pilyugin, L.S. (April 2001). <a rel="nofollow" class="external text" href="https://www.aanda.org/articles/aa/ps/2001/14/aa10396.ps.gz">"On the oxygen abundance determination in H<sup>II</sup> regions"</a>. <i><a href="/wiki/Astronomy_%26_Astrophysics" title="Astronomy & Astrophysics">Astronomy & Astrophysics</a></i>. <b>369</b> (2): <span class="nowrap">594–</span>604. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/astro-ph/0101446">astro-ph/0101446</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2001A&A...369..594P">2001A&A...369..594P</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1051%2F0004-6361%3A20010079">10.1051/0004-6361:20010079</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-6361">0004-6361</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:54527173">54527173</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astronomy+%26+Astrophysics&rft.atitle=On+the+oxygen+abundance+determination+in+H%3Csup%3EII%3C%2Fsup%3E+regions&rft.volume=369&rft.issue=2&rft.pages=%3Cspan+class%3D%22nowrap%22%3E594-%3C%2Fspan%3E604&rft.date=2001-04&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A54527173%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2001A%26A...369..594P&rft_id=info%3Aarxiv%2Fastro-ph%2F0101446&rft.issn=0004-6361&rft_id=info%3Adoi%2F10.1051%2F0004-6361%3A20010079&rft.aulast=Pilyugin&rft.aufirst=L.S.&rft_id=https%3A%2F%2Fwww.aanda.org%2Farticles%2Faa%2Fps%2F2001%2F14%2Faa10396.ps.gz&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-58"><span class="mw-cite-backlink"><b><a href="#cite_ref-58">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKobulnickyZaritsky1999" class="citation journal cs1">Kobulnicky, Henry A.; Zaritsky, Dennis (1999-01-20). "Chemical Properties of Star-forming Emission-Line Galaxies atz=0.1–0.5". <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>511</b> (1): <span class="nowrap">118–</span>135. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/astro-ph/9808081">astro-ph/9808081</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1999ApJ...511..118K">1999ApJ...511..118K</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F306673">10.1086/306673</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-637X">0004-637X</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:13094276">13094276</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=Chemical+Properties+of+Star-forming+Emission-Line+Galaxies+atz%3D0.1%E2%80%930.5&rft.volume=511&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E118-%3C%2Fspan%3E135&rft.date=1999-01-20&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A13094276%23id-name%3DS2CID&rft_id=info%3Abibcode%2F1999ApJ...511..118K&rft_id=info%3Aarxiv%2Fastro-ph%2F9808081&rft.issn=0004-637X&rft_id=info%3Adoi%2F10.1086%2F306673&rft.aulast=Kobulnicky&rft.aufirst=Henry+A.&rft.au=Zaritsky%2C+Dennis&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-59"><span class="mw-cite-backlink"><b><a href="#cite_ref-59">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDiazPerez-Montero2000" class="citation journal cs1">Diaz, A.I.; Perez-Montero, E. (2000-02-11). <a rel="nofollow" class="external text" href="https://doi.org/10.1046%2Fj.1365-8711.2000.03117.x">"An empirical calibration of nebular abundances based on the sulphur emission lines"</a>. <i><a href="/wiki/Monthly_Notices_of_the_Royal_Astronomical_Society" title="Monthly Notices of the Royal Astronomical Society">Monthly Notices of the Royal Astronomical Society</a></i>. <b>312</b> (1): <span class="nowrap">130–</span>138. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/astro-ph/9909492">astro-ph/9909492</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2000MNRAS.312..130D">2000MNRAS.312..130D</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1046%2Fj.1365-8711.2000.03117.x">10.1046/j.1365-8711.2000.03117.x</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0035-8711">0035-8711</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:119504048">119504048</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Monthly+Notices+of+the+Royal+Astronomical+Society&rft.atitle=An+empirical+calibration+of+nebular+abundances+based+on+the+sulphur+emission+lines&rft.volume=312&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E130-%3C%2Fspan%3E138&rft.date=2000-02-11&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A119504048%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2000MNRAS.312..130D&rft_id=info%3Aarxiv%2Fastro-ph%2F9909492&rft.issn=0035-8711&rft_id=info%3Adoi%2F10.1046%2Fj.1365-8711.2000.03117.x&rft.aulast=Diaz&rft.aufirst=A.I.&rft.au=Perez-Montero%2C+E.&rft_id=https%3A%2F%2Fdoi.org%2F10.1046%252Fj.1365-8711.2000.03117.x&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-60"><span class="mw-cite-backlink"><b><a href="#cite_ref-60">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFShaverMcGeeNewtonDanks1983" class="citation journal cs1">Shaver, P.A.; McGee, R.X.; Newton, L.M.; Danks, A.C.; Pottasch, S.R. (1983-09-01). <a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fmnras%2F204.1.53">"The galactic abundance gradient"</a>. <i><a href="/wiki/Monthly_Notices_of_the_Royal_Astronomical_Society" title="Monthly Notices of the Royal Astronomical Society">Monthly Notices of the Royal Astronomical Society</a></i>. <b>204</b> (1): <span class="nowrap">53–</span>112. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1983MNRAS.204...53S">1983MNRAS.204...53S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fmnras%2F204.1.53">10.1093/mnras/204.1.53</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0035-8711">0035-8711</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Monthly+Notices+of+the+Royal+Astronomical+Society&rft.atitle=The+galactic+abundance+gradient&rft.volume=204&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E53-%3C%2Fspan%3E112&rft.date=1983-09-01&rft.issn=0035-8711&rft_id=info%3Adoi%2F10.1093%2Fmnras%2F204.1.53&rft_id=info%3Abibcode%2F1983MNRAS.204...53S&rft.aulast=Shaver&rft.aufirst=P.A.&rft.au=McGee%2C+R.X.&rft.au=Newton%2C+L.M.&rft.au=Danks%2C+A.C.&rft.au=Pottasch%2C+S.R.&rft_id=https%3A%2F%2Fdoi.org%2F10.1093%252Fmnras%252F204.1.53&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-61"><span class="mw-cite-backlink"><b><a href="#cite_ref-61">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAfflerbachChurchwellWerner1997" class="citation journal cs1">Afflerbach, A.; Churchwell, E.; Werner, M. W. (1997-03-20). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F303771">"Galactic abundance gradients from infrared fine-structure lines in compact H<sup>II</sup> regions"</a>. <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>478</b> (1): <span class="nowrap">190–</span>205. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1997ApJ...478..190A">1997ApJ...478..190A</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F303771">10.1086/303771</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-637X">0004-637X</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=Galactic+abundance+gradients+from+infrared+fine-structure+lines+in+compact+H%3Csup%3EII%3C%2Fsup%3E+regions&rft.volume=478&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E190-%3C%2Fspan%3E205&rft.date=1997-03-20&rft.issn=0004-637X&rft_id=info%3Adoi%2F10.1086%2F303771&rft_id=info%3Abibcode%2F1997ApJ...478..190A&rft.aulast=Afflerbach&rft.aufirst=A.&rft.au=Churchwell%2C+E.&rft.au=Werner%2C+M.+W.&rft_id=https%3A%2F%2Fdoi.org%2F10.1086%252F303771&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-62"><span class="mw-cite-backlink"><b><a href="#cite_ref-62">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPagelBernard1997" class="citation book cs1">Pagel, J.; Bernard, E. (1997). <i>Nucleosynthesis and Chemical Evolution of Galaxies</i>. Cambridge University Press. p. 392. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1997nceg.book.....P">1997nceg.book.....P</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-521-55061-1" title="Special:BookSources/978-0-521-55061-1"><bdi>978-0-521-55061-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Nucleosynthesis+and+Chemical+Evolution+of+Galaxies&rft.pages=392&rft.pub=Cambridge+University+Press&rft.date=1997&rft_id=info%3Abibcode%2F1997nceg.book.....P&rft.isbn=978-0-521-55061-1&rft.aulast=Pagel&rft.aufirst=J.&rft.au=Bernard%2C+E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> <li id="cite_note-63"><span class="mw-cite-backlink"><b><a href="#cite_ref-63">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBalserRoodBaniaAnderson2011" class="citation journal cs1">Balser, Dana S.; Rood, Robert T.; Bania, T.M.; Anderson, L.D. (2011-08-10). "H<sup>II</sup> region metallicity distribution in the Milky Way disk". <i><a href="/wiki/The_Astrophysical_Journal" title="The Astrophysical Journal">The Astrophysical Journal</a></i>. <b>738</b> (1): 27. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/1106.1660">1106.1660</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2011ApJ...738...27B">2011ApJ...738...27B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1088%2F0004-637X%2F738%2F1%2F27">10.1088/0004-637X/738/1/27</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0004-637X">0004-637X</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:119252119">119252119</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=H%3Csup%3EII%3C%2Fsup%3E+region+metallicity+distribution+in+the+Milky+Way+disk&rft.volume=738&rft.issue=1&rft.pages=27&rft.date=2011-08-10&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A119252119%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2011ApJ...738...27B&rft_id=info%3Aarxiv%2F1106.1660&rft.issn=0004-637X&rft_id=info%3Adoi%2F10.1088%2F0004-637X%2F738%2F1%2F27&rft.aulast=Balser&rft.aufirst=Dana+S.&rft.au=Rood%2C+Robert+T.&rft.au=Bania%2C+T.M.&rft.au=Anderson%2C+L.D.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></span> </li> </ol></div> <style data-mw-deduplicate="TemplateStyles:r1239549316">.mw-parser-output .refbegin{margin-bottom:0.5em}.mw-parser-output .refbegin-hanging-indents>ul{margin-left:0}.mw-parser-output .refbegin-hanging-indents>ul>li{margin-left:0;padding-left:3.2em;text-indent:-3.2em}.mw-parser-output .refbegin-hanging-indents ul,.mw-parser-output .refbegin-hanging-indents ul li{list-style:none}@media(max-width:720px){.mw-parser-output .refbegin-hanging-indents>ul>li{padding-left:1.6em;text-indent:-1.6em}}.mw-parser-output .refbegin-columns{margin-top:0.3em}.mw-parser-output .refbegin-columns ul{margin-top:0}.mw-parser-output .refbegin-columns li{page-break-inside:avoid;break-inside:avoid-column}@media screen{.mw-parser-output .refbegin{font-size:90%}}</style><div class="refbegin refbegin-columns references-column-width" style="column-width: 25em"> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSalvaterra,_R.Ferrara,_A.Schneider,_R.2004" class="citation journal cs1">Salvaterra, R.; Ferrara, A.; <a href="/wiki/Raffaella_Schneider" title="Raffaella Schneider">Schneider, R.</a> (2004). "Induced formation of primordial low-mass stars". <i><a href="/wiki/New_Astronomy_(journal)" title="New Astronomy (journal)">New Astronomy</a></i>. <b>10</b> (2): <span class="nowrap">113–</span>120. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/astro-ph/0304074">astro-ph/0304074</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2004NewA...10..113S">2004NewA...10..113S</a>. <a href="/wiki/CiteSeerX_(identifier)" class="mw-redirect" title="CiteSeerX (identifier)">CiteSeerX</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.258.923">10.1.1.258.923</a></span>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.newast.2004.06.003">10.1016/j.newast.2004.06.003</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:15085880">15085880</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=New+Astronomy&rft.atitle=Induced+formation+of+primordial+low-mass+stars&rft.volume=10&rft.issue=2&rft.pages=%3Cspan+class%3D%22nowrap%22%3E113-%3C%2Fspan%3E120&rft.date=2004&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A15085880%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2004NewA...10..113S&rft_id=https%3A%2F%2Fciteseerx.ist.psu.edu%2Fviewdoc%2Fsummary%3Fdoi%3D10.1.1.258.923%23id-name%3DCiteSeerX&rft_id=info%3Adoi%2F10.1016%2Fj.newast.2004.06.003&rft_id=info%3Aarxiv%2Fastro-ph%2F0304074&rft.au=Salvaterra%2C+R.&rft.au=Ferrara%2C+A.&rft.au=Schneider%2C+R.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHeger,_A.Woosley,_S.E.2002" class="citation journal cs1">Heger, A.; Woosley, S.E. (2002). "The nucleosynthetic signature of population III". <i><a href="/wiki/Astrophysical_Journal" class="mw-redirect" title="Astrophysical Journal">Astrophysical Journal</a></i>. <b>567</b> (1): <span class="nowrap">532–</span>543. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/astro-ph/0107037">astro-ph/0107037</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2002ApJ...567..532H">2002ApJ...567..532H</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F338487">10.1086/338487</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:16050642">16050642</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astrophysical+Journal&rft.atitle=The+nucleosynthetic+signature+of+population+III&rft.volume=567&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E532-%3C%2Fspan%3E543&rft.date=2002&rft_id=info%3Aarxiv%2Fastro-ph%2F0107037&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A16050642%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1086%2F338487&rft_id=info%3Abibcode%2F2002ApJ...567..532H&rft.au=Heger%2C+A.&rft.au=Woosley%2C+S.E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Metallicity&action=edit&section=14" title="Edit section: Further reading"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKuhnKoupelis2004" class="citation book cs1">Kuhn, Karl F.; Koupelis, Theo (2004). <i>Quest of the Universe</i> (Fourth ed.). Canada: Jones and Bartlett. p. 593. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-7637-0810-0" title="Special:BookSources/0-7637-0810-0"><bdi>0-7637-0810-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Quest+of+the+Universe&rft.place=Canada&rft.pages=593&rft.edition=Fourth&rft.pub=Jones+and+Bartlett&rft.date=2004&rft.isbn=0-7637-0810-0&rft.aulast=Kuhn&rft.aufirst=Karl+F.&rft.au=Koupelis%2C+Theo&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBrommLarson2004" class="citation journal cs1">Bromm, Volker; Larson, Richard B. (2004). "The first stars". <i><a href="/wiki/Annual_Review_of_Astronomy_and_Astrophysics" title="Annual Review of Astronomy and Astrophysics">Annual Review of Astronomy and Astrophysics</a></i>. <b>42</b> (1): <span class="nowrap">79–</span>118. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/astro-ph/0311019">astro-ph/0311019</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2004ARA&A..42...79B">2004ARA&A..42...79B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1146%2Fannurev.astro.42.053102.134034">10.1146/annurev.astro.42.053102.134034</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:119371063">119371063</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Annual+Review+of+Astronomy+and+Astrophysics&rft.atitle=The+first+stars&rft.volume=42&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E79-%3C%2Fspan%3E118&rft.date=2004&rft_id=info%3Aarxiv%2Fastro-ph%2F0311019&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A119371063%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1146%2Fannurev.astro.42.053102.134034&rft_id=info%3Abibcode%2F2004ARA%26A..42...79B&rft.aulast=Bromm&rft.aufirst=Volker&rft.au=Larson%2C+Richard+B.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMetallicity" class="Z3988"></span></li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}</style><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Stars520" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Star" title="Template:Star"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Star" title="Template talk:Star"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Star" title="Special:EditPage/Template:Star"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Stars520" style="font-size:114%;margin:0 4em"><a href="/wiki/Star" title="Star">Stars</a></div></th></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><a href="/wiki/Lists_of_stars" title="Lists of stars">List</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Star_formation" title="Star formation">Formation</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Accretion_(astrophysics)" title="Accretion (astrophysics)">Accretion</a></li> <li><a href="/wiki/Molecular_cloud" title="Molecular cloud">Molecular cloud</a></li> <li><a href="/wiki/Bok_globule" title="Bok globule">Bok globule</a></li> <li><a href="/wiki/Young_stellar_object" title="Young stellar object">Young stellar object</a> <ul><li><a href="/wiki/Protostar" title="Protostar">Protostar</a></li> <li><a href="/wiki/Pre-main-sequence_star" title="Pre-main-sequence star">Pre-main-sequence</a></li> <li><a href="/wiki/Herbig_Ae/Be_star" title="Herbig Ae/Be star">Herbig Ae/Be</a></li> <li><a href="/wiki/T_Tauri_star" title="T Tauri star">T Tauri</a></li></ul></li> <li><a href="/wiki/Herbig%E2%80%93Haro_object" title="Herbig–Haro object">Herbig–Haro object</a></li> <li><a href="/wiki/Hayashi_track" title="Hayashi track">Hayashi track</a></li> <li><a href="/wiki/Henyey_track" title="Henyey track">Henyey track</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Stellar_evolution" title="Stellar evolution">Evolution</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Main_sequence" title="Main sequence">Main sequence</a></li> <li><a href="/wiki/Red-giant_branch" title="Red-giant branch">Red-giant branch</a></li> <li><a href="/wiki/Horizontal_branch" title="Horizontal branch">Horizontal branch</a> <ul><li><a href="/wiki/Red_clump" title="Red clump">Red clump</a></li></ul></li> <li><a href="/wiki/Asymptotic_giant_branch" title="Asymptotic giant branch">Asymptotic giant branch</a> <ul><li><a href="/wiki/Post-AGB_star" title="Post-AGB star">post-AGB</a></li> <li><a href="/wiki/Super-AGB_star" title="Super-AGB star">super-AGB</a></li></ul></li> <li><a href="/wiki/Blue_loop" title="Blue loop">Blue loop</a></li> <li><a href="/wiki/Planetary_nebula" title="Planetary nebula">Planetary nebula</a> <ul><li><a href="/wiki/Protoplanetary_nebula" title="Protoplanetary nebula">Protoplanetary</a></li></ul></li> <li><a href="/wiki/Wolf%E2%80%93Rayet_nebula" title="Wolf–Rayet nebula">Wolf–Rayet nebula</a></li> <li><a href="/wiki/PG_1159_star" title="PG 1159 star">PG1159</a></li> <li><a href="/wiki/Dredge-up" title="Dredge-up">Dredge-up</a></li> <li><a href="/wiki/OH/IR_star" title="OH/IR star">OH/IR</a></li> <li><a href="/wiki/Instability_strip" title="Instability strip">Instability strip</a></li> <li><a href="/wiki/Luminous_blue_variable" title="Luminous blue variable">Luminous blue variable</a></li> <li><a href="/wiki/Stellar_population" title="Stellar population">Stellar population</a></li> <li><a href="/wiki/Supernova" title="Supernova">Supernova</a> <ul><li><a href="/wiki/Superluminous_supernova" title="Superluminous supernova">Superluminous</a></li> <li><a href="/wiki/Hypernova" title="Hypernova">Hypernova</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Stellar_classification" title="Stellar classification">Classification</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Early-type_star" class="mw-redirect" title="Early-type star">Early</a></li> <li><a href="/wiki/Late-type_star" class="mw-redirect" title="Late-type star">Late</a></li> <li>Main sequence <ul><li><a href="/wiki/O-type_main-sequence_star" title="O-type main-sequence star">O</a></li> <li><a href="/wiki/B-type_main-sequence_star" title="B-type main-sequence star">B</a></li> <li><a href="/wiki/A-type_main-sequence_star" title="A-type main-sequence star">A</a></li> <li><a href="/wiki/F-type_main-sequence_star" title="F-type main-sequence star">F</a></li> <li><a href="/wiki/G-type_main-sequence_star" title="G-type main-sequence star">G</a></li> <li><a href="/wiki/K-type_main-sequence_star" title="K-type main-sequence star">K</a></li> <li><a href="/wiki/Red_dwarf" title="Red dwarf">M</a></li></ul></li> <li><a href="/wiki/Subdwarf" title="Subdwarf">Subdwarf</a> <ul><li><a href="/wiki/Subdwarf_O_star" title="Subdwarf O star">O</a></li> <li><a href="/wiki/Subdwarf_B_star" title="Subdwarf B star">B</a></li></ul></li> <li><a href="/wiki/Wolf%E2%80%93Rayet_star" title="Wolf–Rayet star">WR</a></li> <li><a href="/wiki/OB_star" title="OB star">OB</a></li> <li><a href="/wiki/Subgiant" title="Subgiant">Subgiant</a></li> <li><a href="/wiki/Giant_star" title="Giant star">Giant</a> <ul><li><a href="/wiki/Blue_giant" title="Blue giant">Blue</a></li> <li><a href="/wiki/Red_giant" title="Red giant">Red</a></li> <li><a href="/wiki/Yellow_giant" class="mw-redirect" title="Yellow giant">Yellow</a></li></ul></li> <li><a href="/wiki/Bright_giant" class="mw-redirect" title="Bright giant">Bright giant</a></li> <li><a href="/wiki/Supergiant" title="Supergiant">Supergiant</a> <ul><li><a href="/wiki/Blue_supergiant" title="Blue supergiant">Blue</a></li> <li><a href="/wiki/Red_supergiant" title="Red supergiant">Red</a></li> <li><a href="/wiki/Yellow_supergiant" title="Yellow supergiant">Yellow</a></li></ul></li> <li><a href="/wiki/Hypergiant" title="Hypergiant">Hypergiant</a> <ul><li><a href="/wiki/Yellow_hypergiant" title="Yellow hypergiant">Yellow</a></li></ul></li> <li><a href="/wiki/Carbon_star" title="Carbon star">Carbon</a> <ul><li><a href="/wiki/S-type_star" title="S-type star">S</a></li> <li><a href="/wiki/CN_star" title="CN star">CN</a></li> <li><a href="/wiki/CH_star" title="CH star">CH</a></li></ul></li> <li><a href="/wiki/White_dwarf" title="White dwarf">White dwarf</a></li> <li><a href="/wiki/Chemically_peculiar_star" title="Chemically peculiar star">Chemically peculiar</a> <ul><li><a href="/wiki/Am_star" title="Am star">Am</a></li> <li><a href="/wiki/Ap_and_Bp_stars" title="Ap and Bp stars">Ap/Bp</a></li> <li><a href="/wiki/CEMP_star" title="CEMP star">CEMP</a></li> <li><a href="/wiki/Mercury-manganese_star" title="Mercury-manganese star">HgMn</a></li> <li><a href="/wiki/Helium-weak_star" title="Helium-weak star">He-weak</a></li> <li><a href="/wiki/Barium_star" title="Barium star">Barium</a></li> <li><a href="/wiki/Lambda_Bo%C3%B6tis_star" title="Lambda Boötis star">Lambda Boötis</a></li> <li><a href="/wiki/Lead_star" title="Lead star">Lead</a></li> <li><a href="/wiki/Technetium_star" title="Technetium star">Technetium</a></li></ul></li> <li><a href="/wiki/Be_star" title="Be star">Be</a> <ul><li><a href="/wiki/Shell_star" title="Shell star">Shell</a></li></ul></li> <li><a href="/wiki/B(e)_star" title="B(e) star">B[e]</a></li> <li><a href="/wiki/Helium_star" title="Helium star">Helium</a> <ul><li><a href="/wiki/Extreme_helium_star" title="Extreme helium star">Extreme</a></li></ul></li> <li><a href="/wiki/Blue_straggler" title="Blue straggler">Blue straggler</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Compact_star" class="mw-redirect" title="Compact star">Remnants</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Compact_star" class="mw-redirect" title="Compact star">Compact star</a></li> <li><a href="/wiki/IRAS_00500%2B6713" title="IRAS 00500+6713">Parker's star</a></li> <li><a href="/wiki/White_dwarf" title="White dwarf">White dwarf</a> <ul><li><a href="/wiki/Helium_planet" title="Helium planet">Helium planet</a></li></ul></li> <li><a href="/wiki/Neutron_star" title="Neutron star">Neutron</a> <ul><li><a href="/wiki/Radio-quiet_neutron_star" title="Radio-quiet neutron star">Radio-quiet</a></li> <li><a href="/wiki/Pulsar" title="Pulsar">Pulsar</a> <ul><li><a href="/wiki/Binary_pulsar" title="Binary pulsar">Binary</a></li> <li><a href="/wiki/X-ray_pulsar" title="X-ray pulsar">X-ray</a></li></ul></li> <li><a href="/wiki/Magnetar" title="Magnetar">Magnetar</a></li></ul></li> <li><a href="/wiki/Stellar_black_hole" title="Stellar black hole">Stellar black hole</a></li> <li><a href="/wiki/X-ray_binary" title="X-ray binary">X-ray binary</a> <ul><li><a href="/wiki/X-ray_burster" title="X-ray burster">Burster</a></li></ul></li> <li><a href="/wiki/Soft_gamma_repeater" title="Soft gamma repeater">SGR</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Hypothetical_star" title="Hypothetical star">Hypothetical</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Blue_dwarf_(red-dwarf_stage)" title="Blue dwarf (red-dwarf stage)">Blue dwarf</a></li> <li><a href="/wiki/Black_dwarf" title="Black dwarf">Black dwarf</a></li> <li><a href="/wiki/Exotic_star" title="Exotic star">Exotic</a> <ul><li><a href="/wiki/Boson_star" class="mw-redirect" title="Boson star">Boson</a></li> <li><a href="/wiki/Electroweak_star" class="mw-redirect" title="Electroweak star">Electroweak</a></li> <li><a href="/wiki/Strange_star" title="Strange star">Strange</a></li> <li><a href="/wiki/Preon_star" class="mw-redirect" title="Preon star">Preon</a></li> <li><a href="/wiki/Planck_star" title="Planck star">Planck</a></li> <li><a href="/wiki/Dark_star_(dark_matter)" title="Dark star (dark matter)">Dark</a></li> <li><a href="/wiki/Dark-energy_star" title="Dark-energy star">Dark-energy</a></li> <li><a href="/wiki/Quark_star" title="Quark star">Quark</a></li> <li><a href="/wiki/Q_star" title="Q star">Q</a></li></ul></li> <li>Black hole star <ul><li><a href="/wiki/Black_star_(semiclassical_gravity)" title="Black star (semiclassical gravity)">Black</a></li> <li>Hawking</li> <li><a href="/wiki/Quasi-star" title="Quasi-star">Quasi-star</a></li></ul></li> <li><a href="/wiki/Gravastar" title="Gravastar">Gravastar</a></li> <li><a href="/wiki/Thorne%E2%80%93%C5%BBytkow_object" title="Thorne–Żytkow object">Thorne–Żytkow object</a></li> <li><a href="/wiki/Iron_star" title="Iron star">Iron</a></li> <li><a href="/wiki/Blitzar" title="Blitzar">Blitzar</a></li> <li><a href="/wiki/White_hole" title="White hole">White hole</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Stellar_nucleosynthesis" title="Stellar nucleosynthesis">Nucleosynthesis</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Deuterium_fusion" title="Deuterium fusion">Deuterium burning</a></li> <li><a href="/wiki/Lithium_burning" title="Lithium burning">Lithium burning</a></li> <li><a href="/wiki/Proton%E2%80%93proton_chain" title="Proton–proton chain">Proton–proton chain</a></li> <li><a href="/wiki/CNO_cycle" title="CNO cycle">CNO cycle</a></li> <li><a href="/wiki/Helium_flash" title="Helium flash">Helium flash</a></li> <li><a href="/wiki/Triple-alpha_process" title="Triple-alpha process">Triple-alpha process</a></li> <li><a href="/wiki/Alpha_process" title="Alpha process">Alpha process</a></li> <li><a href="/wiki/Carbon-burning_process" title="Carbon-burning process">C burning</a></li> <li><a href="/wiki/Neon-burning_process" title="Neon-burning process">Ne burning</a></li> <li><a href="/wiki/Oxygen-burning_process" title="Oxygen-burning process">O burning</a></li> <li><a href="/wiki/Silicon-burning_process" title="Silicon-burning process">Si burning</a></li> <li><a href="/wiki/S-process" title="S-process">s-process</a></li> <li><a href="/wiki/R-process" title="R-process">r-process</a></li> <li><a href="/wiki/P-process" title="P-process">p-process</a></li> <li><a href="/wiki/Nova" title="Nova">Nova</a> <ul><li><a href="/wiki/Symbiotic_nova" title="Symbiotic nova">Symbiotic</a></li> <li><a href="/wiki/Nova_remnant" title="Nova remnant">Remnant</a></li> <li><a href="/wiki/Luminous_red_nova" title="Luminous red nova">Luminous red nova</a></li> <li><a href="/wiki/Nova#Recurrent_novae" title="Nova">Recurrent</a></li> <li><a href="/wiki/Micronova" title="Micronova">Micronova</a></li></ul></li> <li><a href="/wiki/Supernova_nucleosynthesis" title="Supernova nucleosynthesis">Supernova</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Stellar_structure" title="Stellar structure">Structure</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Stellar_core" title="Stellar core">Core</a></li> <li><a href="/wiki/Convection_zone" title="Convection zone">Convection zone</a> <ul><li><a href="/wiki/Microturbulence" title="Microturbulence">Microturbulence</a></li> <li><a href="/wiki/Solar-like_oscillations" title="Solar-like oscillations">Oscillations</a></li></ul></li> <li><a href="/wiki/Radiation_zone" class="mw-redirect" title="Radiation zone">Radiation zone</a></li> <li><a href="/wiki/Stellar_atmosphere" title="Stellar atmosphere">Atmosphere</a> <ul><li><a href="/wiki/Photosphere" title="Photosphere">Photosphere</a></li> <li><a href="/wiki/Starspot" title="Starspot">Starspot</a></li> <li><a href="/wiki/Chromosphere" title="Chromosphere">Chromosphere</a></li> <li><a href="/wiki/Stellar_corona" title="Stellar corona">Stellar corona</a></li> <li><a href="/wiki/Alfv%C3%A9n_surface" title="Alfvén surface">Alfvén surface</a></li></ul></li> <li><a href="/wiki/Stellar_wind" title="Stellar wind">Stellar wind</a> <ul><li><a href="/wiki/Stellar-wind_bubble" title="Stellar-wind bubble">Bubble</a></li> <li><a href="/wiki/Bipolar_outflow" title="Bipolar outflow">Bipolar outflow</a></li></ul></li> <li><a href="/wiki/Accretion_disk" title="Accretion disk">Accretion disk</a> <ul><li><a href="/wiki/Protoplanetary_disk" title="Protoplanetary disk">Protoplanetary disk</a></li> <li><a href="/wiki/Proplyd" title="Proplyd">Proplyd</a></li></ul></li> <li><a href="/wiki/Asteroseismology" title="Asteroseismology">Asteroseismology</a> <ul><li><a href="/wiki/Helioseismology" title="Helioseismology">Helioseismology</a></li></ul></li> <li><a href="/wiki/Circumstellar_dust" title="Circumstellar dust">Circumstellar dust</a></li> <li><a href="/wiki/Cosmic_dust" title="Cosmic dust">Cosmic dust</a></li> <li><a href="/wiki/Circumstellar_envelope" title="Circumstellar envelope">Circumstellar envelope</a></li> <li><a href="/wiki/Eddington_luminosity" title="Eddington luminosity">Eddington luminosity</a></li> <li><a href="/wiki/Kelvin%E2%80%93Helmholtz_mechanism" title="Kelvin–Helmholtz mechanism">Kelvin–Helmholtz mechanism</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Properties</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Stellar_designations_and_names" title="Stellar designations and names">Designation</a></li> <li><a href="/wiki/Stellar_dynamics" title="Stellar dynamics">Dynamics</a></li> <li><a href="/wiki/Effective_temperature" title="Effective temperature">Effective temperature</a></li> <li><a href="/wiki/Luminosity" title="Luminosity">Luminosity</a></li> <li><a href="/wiki/Stellar_kinematics" title="Stellar kinematics">Kinematics</a></li> <li><a href="/wiki/Stellar_magnetic_field" title="Stellar magnetic field">Magnetic field</a></li> <li><a href="/wiki/Absolute_magnitude" title="Absolute magnitude">Absolute magnitude</a></li> <li><a href="/wiki/Stellar_mass" title="Stellar mass">Mass</a></li> <li><a class="mw-selflink selflink">Metallicity</a></li> <li><a href="/wiki/Stellar_rotation" title="Stellar rotation">Rotation</a></li> <li><a href="/wiki/Starlight" title="Starlight">Starlight</a></li> <li><a href="/wiki/Variable_star" title="Variable star">Variable</a></li> <li><a href="/wiki/Photometric_system" title="Photometric system">Photometric system</a></li> <li><a href="/wiki/Color_index" title="Color index">Color index</a></li> <li><a href="/wiki/Hertzsprung%E2%80%93Russell_diagram" title="Hertzsprung–Russell diagram">Hertzsprung–Russell diagram</a></li> <li><a href="/wiki/Color%E2%80%93color_diagram" title="Color–color diagram">Color–color diagram</a></li> <li><a href="/wiki/Str%C3%B6mgren_sphere" title="Strömgren sphere">Strömgren sphere</a></li> <li><a href="/wiki/Kraft_break" title="Kraft break">Kraft break</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Star_system" title="Star system">Star systems</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Binary_star" title="Binary star">Binary</a> <ul><li><a href="/wiki/Contact_binary" title="Contact binary">Contact</a></li> <li><a href="/wiki/Common_envelope" title="Common envelope">Common envelope</a></li> <li><a href="/wiki/Eclipsing_binary" class="mw-redirect" title="Eclipsing binary">Eclipsing</a></li> <li><a href="/wiki/Symbiotic_binary" title="Symbiotic binary">Symbiotic</a></li></ul></li> <li><a href="/wiki/Star_system#Multiple_star_systems" title="Star system">Multiple</a></li> <li><a href="/wiki/Star_cluster" title="Star cluster">Cluster</a> <ul><li><a href="/wiki/Open_cluster" title="Open cluster">Open</a></li> <li><a href="/wiki/Globular_cluster" title="Globular cluster">Globular</a></li> <li><a href="/wiki/Super_star_cluster" title="Super star cluster">Super</a></li></ul></li> <li><a href="/wiki/Planetary_system" title="Planetary system">Planetary system</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Earth-centric<br />observations</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Sun" title="Sun">Sun</a> <ul><li><a href="/wiki/Solar_eclipse" title="Solar eclipse">Solar eclipse</a></li> <li><a href="/wiki/Solar_radio_emission" title="Solar radio emission">Solar radio emission</a></li> <li><a href="/wiki/Solar_System" title="Solar System">Solar System</a></li> <li><a href="/wiki/Sunlight" title="Sunlight">Sunlight</a></li></ul></li> <li><a href="/wiki/Pole_star" title="Pole star">Pole star</a></li> <li><a href="/wiki/Circumpolar_star" title="Circumpolar star">Circumpolar</a></li> <li><a href="/wiki/Constellation" title="Constellation">Constellation</a></li> <li><a href="/wiki/Asterism_(astronomy)" title="Asterism (astronomy)">Asterism</a></li> <li><a href="/wiki/Magnitude_(astronomy)" title="Magnitude (astronomy)">Magnitude</a> <ul><li><a href="/wiki/Apparent_magnitude" title="Apparent magnitude">Apparent</a></li> <li><a href="/wiki/Extinction_(astronomy)" title="Extinction (astronomy)">Extinction</a></li> <li><a href="/wiki/Photographic_magnitude" title="Photographic magnitude">Photographic</a></li></ul></li> <li><a href="/wiki/Radial_velocity" title="Radial velocity">Radial velocity</a></li> <li><a href="/wiki/Proper_motion" title="Proper motion">Proper motion</a></li> <li><a href="/wiki/Stellar_parallax" title="Stellar parallax">Parallax</a></li> <li><a href="/wiki/Photometric-standard_star" title="Photometric-standard star">Photometric-standard</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Lists_of_stars" title="Lists of stars">Lists</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_proper_names_of_stars" title="List of proper names of stars">Proper names</a> <ul><li><a href="/wiki/List_of_Arabic_star_names" title="List of Arabic star names">Arabic</a></li> <li><a href="/wiki/Chinese_star_names" class="mw-redirect" title="Chinese star names">Chinese</a></li></ul></li> <li><a href="/wiki/List_of_star_extremes" title="List of star extremes">Extremes</a> <ul><li><a href="/wiki/List_of_most_massive_stars" title="List of most massive stars">Most massive</a></li> <li><a href="/wiki/List_of_hottest_stars" title="List of hottest stars">Highest temperature</a></li> <li><a href="/wiki/List_of_coolest_stars" title="List of coolest stars">Lowest temperature</a></li> <li><a href="/wiki/List_of_largest_known_stars" class="mw-redirect" title="List of largest known stars">Largest volume</a></li> <li><a href="/wiki/List_of_smallest_known_stars" title="List of smallest known stars">Smallest volume</a></li> <li><a href="/wiki/List_of_brightest_stars" title="List of brightest stars">Brightest</a></li> <li><a href="/wiki/Historical_brightest_stars" title="Historical brightest stars">Historical brightest</a></li> <li><a href="/wiki/List_of_most_luminous_stars" title="List of most luminous stars">Most luminous</a></li> <li><a href="/wiki/List_of_nearest_stars" title="List of nearest stars">Nearest</a> <ul><li><a href="/wiki/List_of_nearest_bright_stars" title="List of nearest bright stars">bright</a></li></ul></li> <li><a href="/wiki/List_of_the_most_distant_astronomical_objects#List_of_most_distant_objects_by_type" title="List of the most distant astronomical objects">Most distant</a></li></ul></li> <li><a href="/wiki/List_of_stars_with_resolved_images" title="List of stars with resolved images">With resolved images</a></li> <li><a href="/wiki/List_of_multiplanetary_systems" title="List of multiplanetary systems">With multiple exoplanets</a></li> <li><a href="/wiki/List_of_brown_dwarfs" title="List of brown dwarfs">Brown dwarfs</a></li> <li><a href="/wiki/List_of_red_dwarfs" title="List of red dwarfs">Red dwarfs</a></li> <li><a href="/wiki/List_of_white_dwarfs" title="List of white dwarfs">White dwarfs</a></li> <li><a href="/wiki/List_of_novae_in_the_Milky_Way_galaxy" title="List of novae in the Milky Way galaxy">Milky Way novae</a></li> <li><a href="/wiki/List_of_supernovae" title="List of supernovae">Supernovae</a> <ul><li><a href="/wiki/List_of_supernova_candidates" title="List of supernova candidates">Candidates</a></li> <li><a href="/wiki/List_of_supernova_remnants" title="List of supernova remnants">Remnants</a></li></ul></li> <li><a href="/wiki/List_of_planetary_nebulae" title="List of planetary nebulae">Planetary nebulae</a></li> <li><a href="/wiki/Timeline_of_stellar_astronomy" title="Timeline of stellar astronomy">Timeline of stellar astronomy</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Substellar_object" title="Substellar object">Substellar object</a> <ul><li><a href="/wiki/Brown_dwarf" title="Brown dwarf">Brown dwarf</a> <ul><li><a href="/wiki/Brown-dwarf_desert" title="Brown-dwarf desert">Desert</a></li> <li><a href="/wiki/Sub-brown_dwarf" title="Sub-brown dwarf">Sub</a></li></ul></li> <li><a href="/wiki/Planet" title="Planet">Planet</a></li></ul></li> <li><a href="/wiki/Galactic_year" title="Galactic year">Galactic year</a></li> <li><a href="/wiki/Galaxy" title="Galaxy">Galaxy</a></li> <li><a href="/wiki/Guest_star_(astronomy)" title="Guest star (astronomy)">Guest</a></li> <li><a href="/wiki/Gravity" title="Gravity">Gravity</a></li> <li><a href="/wiki/Intergalactic_star" title="Intergalactic star">Intergalactic</a></li> <li><a href="/wiki/Planet-hosting_stars" class="mw-redirect" title="Planet-hosting stars">Planet-hosting stars</a></li> <li><a href="/wiki/Tidal_disruption_event" title="Tidal disruption event">Tidal disruption event</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Stars" title="Category:Stars">Category</a></li> <li><span class="nowrap"><span class="noviewer" typeof="mw:File"><a href="/wiki/File:He1523a.jpg" class="mw-file-description"><img alt="icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/5/5f/He1523a.jpg/14px-He1523a.jpg" decoding="async" width="14" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5f/He1523a.jpg/21px-He1523a.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5f/He1523a.jpg/28px-He1523a.jpg 2x" data-file-width="180" data-file-height="207" /></a></span> </span><a href="/wiki/Portal:Stars" title="Portal:Stars">Stars portal</a></li></ul> </div></td></tr></tbody></table></div> <style data-mw-deduplicate="TemplateStyles:r1130092004">.mw-parser-output .portal-bar{font-size:88%;font-weight:bold;display:flex;justify-content:center;align-items:baseline}.mw-parser-output .portal-bar-bordered{padding:0 2em;background-color:#fdfdfd;border:1px solid #a2a9b1;clear:both;margin:1em auto 0}.mw-parser-output .portal-bar-related{font-size:100%;justify-content:flex-start}.mw-parser-output .portal-bar-unbordered{padding:0 1.7em;margin-left:0}.mw-parser-output .portal-bar-header{margin:0 1em 0 0.5em;flex:0 0 auto;min-height:24px}.mw-parser-output .portal-bar-content{display:flex;flex-flow:row wrap;flex:0 1 auto;padding:0.15em 0;column-gap:1em;align-items:baseline;margin:0;list-style:none}.mw-parser-output .portal-bar-content-related{margin:0;list-style:none}.mw-parser-output .portal-bar-item{display:inline-block;margin:0.15em 0.2em;min-height:24px;line-height:24px}@media screen and (max-width:768px){.mw-parser-output .portal-bar{font-size:88%;font-weight:bold;display:flex;flex-flow:column wrap;align-items:baseline}.mw-parser-output .portal-bar-header{text-align:center;flex:0;padding-left:0.5em;margin:0 auto}.mw-parser-output .portal-bar-related{font-size:100%;align-items:flex-start}.mw-parser-output .portal-bar-content{display:flex;flex-flow:row wrap;align-items:center;flex:0;column-gap:1em;border-top:1px solid #a2a9b1;margin:0 auto;list-style:none}.mw-parser-output .portal-bar-content-related{border-top:none;margin:0;list-style:none}}.mw-parser-output .navbox+link+.portal-bar,.mw-parser-output .navbox+style+.portal-bar,.mw-parser-output .navbox+link+.portal-bar-bordered,.mw-parser-output .navbox+style+.portal-bar-bordered,.mw-parser-output .sister-bar+link+.portal-bar,.mw-parser-output .sister-bar+style+.portal-bar,.mw-parser-output .portal-bar+.navbox-styles+.navbox,.mw-parser-output .portal-bar+.navbox-styles+.sister-bar{margin-top:-1px}</style><div class="portal-bar noprint metadata noviewer portal-bar-bordered" role="navigation" aria-label="Portals"><span class="portal-bar-header"><a href="/wiki/Wikipedia:Contents/Portals" title="Wikipedia:Contents/Portals">Portals</a>:</span><ul class="portal-bar-content"><li class="portal-bar-item"><span class="nowrap"><span typeof="mw:File"><a href="/wiki/File:Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg" class="mw-file-description"><img alt="icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/17px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png" decoding="async" width="17" height="19" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/26px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/34px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png 2x" data-file-width="530" data-file-height="600" /></a></span> </span><a href="/wiki/Portal:Physics" title="Portal:Physics">Physics</a></li><li class="portal-bar-item"><span class="nowrap"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/e/ed/Papapishu-Lab-icon-6.svg/19px-Papapishu-Lab-icon-6.svg.png" decoding="async" width="19" height="19" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/ed/Papapishu-Lab-icon-6.svg/29px-Papapishu-Lab-icon-6.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/ed/Papapishu-Lab-icon-6.svg/38px-Papapishu-Lab-icon-6.svg.png 2x" data-file-width="512" data-file-height="512" /></span></span> </span><a href="/wiki/Portal:Chemistry" title="Portal:Chemistry">Chemistry</a></li><li class="portal-bar-item"><span class="nowrap"><span typeof="mw:File"><a href="/wiki/File:Nuvola_apps_edu_mathematics_blue-p.svg" class="mw-file-description"><img alt="icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Nuvola_apps_edu_mathematics_blue-p.svg/19px-Nuvola_apps_edu_mathematics_blue-p.svg.png" decoding="async" width="19" height="19" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Nuvola_apps_edu_mathematics_blue-p.svg/29px-Nuvola_apps_edu_mathematics_blue-p.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Nuvola_apps_edu_mathematics_blue-p.svg/38px-Nuvola_apps_edu_mathematics_blue-p.svg.png 2x" data-file-width="128" data-file-height="128" /></a></span> </span><a href="/wiki/Portal:Mathematics" title="Portal:Mathematics">Mathematics</a></li><li class="portal-bar-item"><span class="nowrap"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/00/Crab_Nebula.jpg/19px-Crab_Nebula.jpg" decoding="async" width="19" height="19" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/00/Crab_Nebula.jpg/29px-Crab_Nebula.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/00/Crab_Nebula.jpg/38px-Crab_Nebula.jpg 2x" data-file-width="3864" data-file-height="3864" /></span></span> </span><a href="/wiki/Portal:Astronomy" title="Portal:Astronomy">Astronomy</a></li><li class="portal-bar-item"><span class="nowrap"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/5/5c/Earth-moon.jpg/21px-Earth-moon.jpg" decoding="async" width="21" height="17" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5c/Earth-moon.jpg/32px-Earth-moon.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5c/Earth-moon.jpg/42px-Earth-moon.jpg 2x" data-file-width="3000" data-file-height="2400" /></span></span> </span><a href="/wiki/Portal:Outer_space" title="Portal:Outer space">Outer space</a></li><li class="portal-bar-item"><span class="nowrap"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/8/83/Solar_system.jpg/15px-Solar_system.jpg" decoding="async" width="15" height="19" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/83/Solar_system.jpg/23px-Solar_system.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/83/Solar_system.jpg/30px-Solar_system.jpg 2x" data-file-width="4500" data-file-height="5600" /></span></span> </span><a href="/wiki/Portal:Solar_System" title="Portal:Solar System">Solar System</a></li><li class="portal-bar-item"><span class="nowrap"><span typeof="mw:File"><a href="/wiki/File:Nuvola_apps_kalzium.svg" class="mw-file-description"><img alt="icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/8/8b/Nuvola_apps_kalzium.svg/19px-Nuvola_apps_kalzium.svg.png" decoding="async" width="19" height="19" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/8b/Nuvola_apps_kalzium.svg/29px-Nuvola_apps_kalzium.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/8b/Nuvola_apps_kalzium.svg/38px-Nuvola_apps_kalzium.svg.png 2x" data-file-width="128" data-file-height="128" /></a></span> </span><a href="/wiki/Portal:Science" title="Portal:Science">Science</a></li></ul></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?useformat=desktop&type=1x1&usesul3=0" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Metallicity&oldid=1272295754">https://en.wikipedia.org/w/index.php?title=Metallicity&oldid=1272295754</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:Concepts_in_astrophysics" title="Category:Concepts in astrophysics">Concepts in astrophysics</a></li><li><a href="/wiki/Category:Concepts_in_astronomy" title="Category:Concepts in astronomy">Concepts in astronomy</a></li><li><a href="/wiki/Category:Physical_cosmology" title="Category:Physical cosmology">Physical cosmology</a></li><li><a href="/wiki/Category:Stellar_astronomy" title="Category:Stellar astronomy">Stellar astronomy</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:All_articles_with_broken_links_to_citations" title="Category:All articles with broken links to citations">All articles with broken links to citations</a></li><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_is_different_from_Wikidata" title="Category:Short description is different from Wikidata">Short description is different from Wikidata</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 28 January 2025, at 00:06<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. By using this site, you agree to the <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use" class="extiw" title="foundation:Special:MyLanguage/Policy:Terms of Use">Terms of Use</a> and <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy" class="extiw" title="foundation:Special:MyLanguage/Policy:Privacy policy">Privacy Policy</a>. Wikipedia® is a registered trademark of the <a rel="nofollow" class="external text" href="https://wikimediafoundation.org/">Wikimedia Foundation, Inc.</a>, a non-profit organization.</li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:About">About Wikipedia</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:General_disclaimer">Disclaimers</a></li> <li id="footer-places-contact"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikipedia.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikipedia.org/w/index.php?title=Metallicity&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" lang="en" loading="lazy"></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><picture><source media="(min-width: 500px)" srcset="/w/resources/assets/poweredby_mediawiki.svg" width="88" height="31"><img src="/w/resources/assets/mediawiki_compact.svg" alt="Powered by MediaWiki" width="25" height="25" loading="lazy"></picture></a></li> </ul> </footer> </div> </div> </div> <div class="vector-header-container vector-sticky-header-container"> <div id="vector-sticky-header" class="vector-sticky-header"> <div class="vector-sticky-header-start"> <div class="vector-sticky-header-icon-start vector-button-flush-left vector-button-flush-right" aria-hidden="true"> <button class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-sticky-header-search-toggle" tabindex="-1" data-event-name="ui.vector-sticky-search-form.icon"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </button> </div> <div role="search" class="vector-search-box-vue vector-search-box-show-thumbnail vector-search-box"> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail"> <form action="/w/index.php" id="vector-sticky-search-form" class="cdx-search-input cdx-search-input--has-end-button"> <div class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia"> <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <div class="vector-sticky-header-context-bar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-sticky-header-toc" class="vector-dropdown mw-portlet mw-portlet-sticky-header-toc vector-sticky-header-toc vector-button-flush-left" > <input type="checkbox" id="vector-sticky-header-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-sticky-header-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-sticky-header-toc-label" for="vector-sticky-header-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-sticky-header-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div class="vector-sticky-header-context-bar-primary" aria-hidden="true" ><span class="mw-page-title-main">Metallicity</span></div> </div> </div> <div class="vector-sticky-header-end" aria-hidden="true"> <div class="vector-sticky-header-icons"> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-talk-sticky-header" tabindex="-1" data-event-name="talk-sticky-header"><span class="vector-icon mw-ui-icon-speechBubbles mw-ui-icon-wikimedia-speechBubbles"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-subject-sticky-header" tabindex="-1" data-event-name="subject-sticky-header"><span class="vector-icon mw-ui-icon-article mw-ui-icon-wikimedia-article"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-history-sticky-header" tabindex="-1" data-event-name="history-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-history mw-ui-icon-wikimedia-wikimedia-history"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only mw-watchlink" id="ca-watchstar-sticky-header" tabindex="-1" data-event-name="watch-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-star mw-ui-icon-wikimedia-wikimedia-star"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-edit-sticky-header" tabindex="-1" data-event-name="wikitext-edit-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-wikiText mw-ui-icon-wikimedia-wikimedia-wikiText"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-ve-edit-sticky-header" tabindex="-1" data-event-name="ve-edit-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-edit mw-ui-icon-wikimedia-wikimedia-edit"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-viewsource-sticky-header" tabindex="-1" data-event-name="ve-edit-protected-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-editLock mw-ui-icon-wikimedia-wikimedia-editLock"></span> <span></span> </a> </div> <div class="vector-sticky-header-buttons"> <button class="cdx-button cdx-button--weight-quiet mw-interlanguage-selector" id="p-lang-btn-sticky-header" tabindex="-1" data-event-name="ui.dropdown-p-lang-btn-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-language mw-ui-icon-wikimedia-wikimedia-language"></span> <span>51 languages</span> </button> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive" id="ca-addsection-sticky-header" tabindex="-1" data-event-name="addsection-sticky-header"><span class="vector-icon mw-ui-icon-speechBubbleAdd-progressive mw-ui-icon-wikimedia-speechBubbleAdd-progressive"></span> <span>Add topic</span> </a> </div> <div class="vector-sticky-header-icon-end"> <div class="vector-user-links"> </div> </div> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-6b9576b97f-vqd94","wgBackendResponseTime":150,"wgPageParseReport":{"limitreport":{"cputime":"1.415","walltime":"1.783","ppvisitednodes":{"value":5605,"limit":1000000},"postexpandincludesize":{"value":210791,"limit":2097152},"templateargumentsize":{"value":1906,"limit":2097152},"expansiondepth":{"value":16,"limit":100},"expensivefunctioncount":{"value":13,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":270258,"limit":5000000},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 1338.115 1 -total"," 58.36% 780.895 1 Template:Reflist"," 31.81% 425.695 47 Template:Cite_journal"," 12.56% 168.030 9 Template:Cite_book"," 11.84% 158.470 1 Template:Star"," 11.66% 156.069 2 Template:Navbox"," 6.82% 91.211 1 Template:Short_description"," 4.66% 62.406 2 Template:Pagetype"," 4.46% 59.635 1 Template:Portal_bar"," 3.67% 49.167 1 Template:Citation_not_found"]},"scribunto":{"limitreport-timeusage":{"value":"0.892","limit":"10.000"},"limitreport-memusage":{"value":9634612,"limit":52428800},"limitreport-logs":"table#1 {\n [\"size\"] = \"tiny\",\n}\n"},"cachereport":{"origin":"mw-web.codfw.main-65b64b4b74-ztc8v","timestamp":"20250219130222","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"Metallicity","url":"https:\/\/en.wikipedia.org\/wiki\/Metallicity","sameAs":"http:\/\/www.wikidata.org\/entity\/Q217030","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q217030","author":{"@type":"Organization","name":"Contributors to Wikimedia projects"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2004-11-03T21:57:07Z","dateModified":"2025-01-28T00:06:16Z","image":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/6\/6a\/A_Swarm_of_Ancient_Stars_-_GPN-2000-000930.jpg","headline":"fraction of mass of a star or other kind of astronomical object that is not in hydrogen or helium"}</script> </body> </html>