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The End of the Main Sequence - NASA/ADS

<!DOCTYPE html> <!--[if lt IE 7]> <html class="no-js lt-ie9 lt-ie8 lt-ie7"> <![endif]--> <!--[if IE 7]> <html class="no-js lt-ie9 lt-ie8"> <![endif]--> <!--[if IE 8]> <html class="no-js lt-ie9"> <![endif]--> <!--[if gt IE 8]><!--> <html class="no-js" lang="en"> <!--<![endif]--> <head> <title>The End of the Main Sequence - NASA/ADS</title> <!-- favicon --> <link rel="apple-touch-icon" sizes="180x180" href="//styles/favicon/apple-touch-icon.png" /> <link rel="icon" type="image/png" sizes="32x32" href="//styles/favicon/favicon-32x32.png" /> <link rel="icon" type="image/png" sizes="16x16" href="//styles/favicon/favicon-16x16.png" /> <link rel="manifest" href="//styles/favicon/site.webmanifest" /> <link rel="mask-icon" href="//styles/favicon/safari-pinned-tab.svg" color="#5bbad5" /> <meta name="apple-mobile-web-app-title" content="NASA ADS" /> <meta name="application-name" content="NASA ADS" /> <meta name="msapplication-TileColor" content="#ffc40d" /> <meta name="theme-color" content="#ffffff" /> <!-- /favicon --> <link rel="stylesheet" href="/styles/css/styles.css"> <meta name="robots" content="noarchive"> <link rel="canonical" href="http://ui.adsabs.harvard.edu/abs/1997ApJ...482..420L/abstract"/> <meta name="description" content="We present stellar evolution calculations for the lowest mass stars, i.e., those stars with masses in the range 0.08 M&lt;SUB&gt;⊙&lt;/SUB&gt; &amp;lt;= M&lt;SUB&gt;*&lt;/SUB&gt; &amp;lt;= 0.25 M&lt;SUB&gt;⊙&lt;/SUB&gt;. Our particular emphasis is on the post-main-sequence evolution of these objects. We establish a hydrogen-burning timescale of τ&lt;SUB&gt;H&lt;/SUB&gt; ~ 1.0 × 10&lt;SUP&gt;13&lt;/SUP&gt; years for the minimum-mass main-sequence star. This timescale determines the duration over which the light of our Galaxy is dominated by a conventional stellar contribution. We find that for masses M&lt;SUB&gt;*&lt;/SUB&gt; &amp;lt; 0.25 M&lt;SUB&gt;⊙&lt;/SUB&gt;, stars remain fully convective for a significant fraction of the duration of their evolution. The maintenance of full convection precludes the development of large composition gradients and allows the entire star to build up a large helium mass fraction. We find that stars with masses M &amp;lt; 0.20 M&lt;SUB&gt;⊙&lt;/SUB&gt; will never evolve through a red giant stage. After becoming gradually brighter and bluer for trillions of years, these late M dwarfs of today will develop radiative-conductive cores and mild nuclear shell sources; these stars then end their lives as helium white dwarfs. Our work has significant bearing on the general question of why stars become red giants. The fact that the lowest mass stars grow neither red nor giant as they evolve provides an important insight into this problem. Through both analytical and numerical arguments, we have determined that the development of low-mass red giants requires a combination of (1) increasing core luminosity, (2) the existence of molecular weight gradients between the core and the envelope, and (3) the presence of an atmospheric opacity which is an increasing function of temperature. Finally, we discuss the implications of our results with regards to the long-term fate and evolution of the Galaxy."> <!-- Open Graph --> <meta property="og:type" content="article"> <meta property="og:title" content="The End of the Main Sequence"> <meta property="og:site_name" content="NASA/ADS"> <meta property="og:description" content="We present stellar evolution calculations for the lowest mass stars, i.e., those stars with masses in the range 0.08 M&lt;SUB&gt;⊙&lt;/SUB&gt; &amp;lt;= M&lt;SUB&gt;*&lt;/SUB&gt; &amp;lt;= 0.25 M&lt;SUB&gt;⊙&lt;/SUB&gt;. Our particular emphasis is on the post-main-sequence evolution of these objects. We establish a hydrogen-burning timescale of τ&lt;SUB&gt;H&lt;/SUB&gt; ~ 1.0 × 10&lt;SUP&gt;13&lt;/SUP&gt; years for the minimum-mass main-sequence star. This timescale determines the duration over which the light of our Galaxy is dominated by a conventional stellar contribution. We find that for masses M&lt;SUB&gt;*&lt;/SUB&gt; &amp;lt; 0.25 M&lt;SUB&gt;⊙&lt;/SUB&gt;, stars remain fully convective for a significant fraction of the duration of their evolution. The maintenance of full convection precludes the development of large composition gradients and allows the entire star to build up a large helium mass fraction. We find that stars with masses M &amp;lt; 0.20 M&lt;SUB&gt;⊙&lt;/SUB&gt; will never evolve through a red giant stage. After becoming gradually brighter and bluer for trillions of years, these late M dwarfs of today will develop radiative-conductive cores and mild nuclear shell sources; these stars then end their lives as helium white dwarfs. Our work has significant bearing on the general question of why stars become red giants. The fact that the lowest mass stars grow neither red nor giant as they evolve provides an important insight into this problem. Through both analytical and numerical arguments, we have determined that the development of low-mass red giants requires a combination of (1) increasing core luminosity, (2) the existence of molecular weight gradients between the core and the envelope, and (3) the presence of an atmospheric opacity which is an increasing function of temperature. Finally, we discuss the implications of our results with regards to the long-term fate and evolution of the Galaxy."> <meta property="og:url" content="https://ui.adsabs.harvard.edu/abs/1997ApJ...482..420L/abstract"> <meta property="og:image" content="https://ui.adsabs.harvard.edu/styles/img/transparent_logo.svg"> <meta property="article:published_time" content="06/1997"> <meta property="article:author" content="Laughlin, Gregory"> <meta property="article:author" content="Bodenheimer, Peter"> <meta property="article:author" content="Adams, Fred C."> <!-- citation_* --> <meta name="citation_journal_title" content="The Astrophysical Journal"> <meta name="citation_authors" content="Laughlin, Gregory;Bodenheimer, Peter;Adams, Fred C."> <meta name="citation_title" content="The End of the Main Sequence"> <meta name="citation_date" content="06/1997"> <meta name="citation_volume" content="482"> <meta name="citation_issue" content="1"> <meta name="citation_firstpage" content="420"> <meta name="citation_doi" content="10.1086/304125"> <meta name="citation_issn" content="0004-637X"> <meta name="citation_language" content="en"> <meta name="citation_keywords" content="Stars: Evolution"> <meta name="citation_keywords" content="Stars: Interiors"> <meta name="citation_keywords" content="Stars: Late-Type"> <meta name="citation_keywords" content="Stars: Low-Mass"> <meta name="citation_keywords" content="Brown Dwarfs"> <meta name="citation_abstract_html_url" content="https://ui.adsabs.harvard.edu/abs/1997ApJ...482..420L/abstract"> <meta name="citation_publication_date" content="06/1997"> <meta name="citation_lastpage" content="432" /> <link title="schema(PRISM)" rel="schema.prism" href="http://prismstandard.org/namespaces/1.2/basic/" /> <meta name="prism.publicationDate" content="06/1997" /> <meta name="prism.publicationName" content="ApJ" /> <meta name="prism.issn" content="0004-637X" /> <meta name="prism.volume" content="482" /> <meta name="prism.startingPage" content="420" /> <meta name="prism.endingPage" content="432" /> <link title="schema(DC)" rel="schema.dc" href="http://purl.org/dc/elements/1.1/" /> <meta name="dc.identifier" content="doi:10.1086/304125" /> <meta name="dc.date" content="06/1997" /> <meta name="dc.source" content="ApJ" /> <meta name="dc.title" content="The End of the Main Sequence" /> <meta name="dc.creator" content="Laughlin, Gregory"> <meta name="dc.creator" content="Bodenheimer, Peter"> <meta name="dc.creator" content="Adams, Fred C."> <!-- twitter card --> <meta name="twitter:card" content="summary_large_image"/> <meta name="twitter:description" content="We present stellar evolution calculations for the lowest mass stars, i.e., those stars with masses in the range 0.08 M&lt;SUB&gt;⊙&lt;/SUB&gt; &amp;lt;= M&lt;SUB&gt;*&lt;/SUB&gt; &amp;lt;= 0.25 M&lt;SUB&gt;⊙&lt;/SUB&gt;. Our particular emphasis is on the post-main-sequence evolution of these objects. We establish a hydrogen-burning timescale of τ&lt;SUB&gt;H&lt;/SUB&gt; ~ 1.0 × 10&lt;SUP&gt;13&lt;/SUP&gt; years for the minimum-mass main-sequence star. This timescale determines the duration over which the light of our Galaxy is dominated by a conventional stellar contribution. We find that for masses M&lt;SUB&gt;*&lt;/SUB&gt; &amp;lt; 0.25 M&lt;SUB&gt;⊙&lt;/SUB&gt;, stars remain fully convective for a significant fraction of the duration of their evolution. The maintenance of full convection precludes the development of large composition gradients and allows the entire star to build up a large helium mass fraction. We find that stars with masses M &amp;lt; 0.20 M&lt;SUB&gt;⊙&lt;/SUB&gt; will never evolve through a red giant stage. After becoming gradually brighter and bluer for trillions of years, these late M dwarfs of today will develop radiative-conductive cores and mild nuclear shell sources; these stars then end their lives as helium white dwarfs. Our work has significant bearing on the general question of why stars become red giants. The fact that the lowest mass stars grow neither red nor giant as they evolve provides an important insight into this problem. Through both analytical and numerical arguments, we have determined that the development of low-mass red giants requires a combination of (1) increasing core luminosity, (2) the existence of molecular weight gradients between the core and the envelope, and (3) the presence of an atmospheric opacity which is an increasing function of temperature. Finally, we discuss the implications of our results with regards to the long-term fate and evolution of the Galaxy."/> <meta name="twitter:title" content="The End of the Main Sequence"/> <meta name="twitter:site" content="@adsabs"/> <meta name="twitter:domain" content="NASA/ADS"/> <meta name="twitter:image:src" content="https://ui.adsabs.harvard.edu/styles/img/transparent_logo.svg"/> <meta name="twitter:creator" content="@adsabs"/> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no"> <base href="/"> <style> .btn-full-ads { color: #fff !important; background-color: #1a1a1a !important; border-color: #1a1a1a !important; margin-top: 9px !important; padding-bottom: 10px !important; padding-top: 10px !important; } .btn-full-ads:hover, .btn-full-ads:focus, .btn-full-ads:active, .btn-full-ads.active, .open>.dropdown-toggle.btn-full-ads { color: #000 !important; background-color: #ddd !important; border-color: #1a1a1a !important; } .dropdown-toggle:hover .dropdown-menu { display: block; 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<li class="author"><a href="/search/?q=author%3A%22Bodenheimer%2C+Peter%22">Bodenheimer, Peter</a> </li>; <li class="author"><a href="/search/?q=author%3A%22Adams%2C+Fred+C.%22">Adams, Fred C.</a> </li> </ul> </div> <div class="s-abstract-text"> <h4 class="sr-only">Abstract</h4> <p> We present stellar evolution calculations for the lowest mass stars, i.e., those stars with masses in the range 0.08 M<SUB>⊙</SUB> &lt;= M<SUB>*</SUB> &lt;= 0.25 M<SUB>⊙</SUB>. Our particular emphasis is on the post-main-sequence evolution of these objects. We establish a hydrogen-burning timescale of τ<SUB>H</SUB> ~ 1.0 × 10<SUP>13</SUP> years for the minimum-mass main-sequence star. This timescale determines the duration over which the light of our Galaxy is dominated by a conventional stellar contribution. We find that for masses M<SUB>*</SUB> &lt; 0.25 M<SUB>⊙</SUB>, stars remain fully convective for a significant fraction of the duration of their evolution. The maintenance of full convection precludes the development of large composition gradients and allows the entire star to build up a large helium mass fraction. We find that stars with masses M &lt; 0.20 M<SUB>⊙</SUB> will never evolve through a red giant stage. After becoming gradually brighter and bluer for trillions of years, these late M dwarfs of today will develop radiative-conductive cores and mild nuclear shell sources; these stars then end their lives as helium white dwarfs. Our work has significant bearing on the general question of why stars become red giants. The fact that the lowest mass stars grow neither red nor giant as they evolve provides an important insight into this problem. Through both analytical and numerical arguments, we have determined that the development of low-mass red giants requires a combination of (1) increasing core luminosity, (2) the existence of molecular weight gradients between the core and the envelope, and (3) the presence of an atmospheric opacity which is an increasing function of temperature. Finally, we discuss the implications of our results with regards to the long-term fate and evolution of the Galaxy. </p> </div> <br> <dl class="s-abstract-dl-horizontal"> <dt>Publication:</dt> <dd> <div id="article-publication">The Astrophysical Journal</div> </dd> <dt>Pub Date:</dt> <dd>June 1997</dd> <dt>DOI:</dt> <dd> <span> <a href="/link_gateway/1997ApJ...482..420L/doi:10.1086/304125" target="_blank" rel="noopener">10.1086/304125</a> <i class="fa fa-external-link"></i> </span> </dd> <dt>Bibcode:</dt> <dd> <a href="/abs/1997ApJ...482..420L/abstract"> 1997ApJ...482..420L </a> <i class="icon-help" title="The bibcode is assigned by the ADS as a unique identifier for the paper."></i> </dd> <dt>Keywords:</dt> <dd> <ul class="list-inline"> <li>Stars: Evolution;</li> <li>Stars: Interiors;</li> <li>Stars: Late-Type;</li> <li>Stars: Low-Mass;</li> <li>Brown Dwarfs</li> </ul> </dd> </dl> </article> </div> <div data-widget="ShowCitations"></div> <div data-widget="ShowReferences"></div> <div 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b.innerHTML += autoValues[i].match.substr(val.length); } // Insert a input field that will hold the current array item's value: b.innerHTML += "<input type='hidden' value='" + autoValues[i].value + "'>"; // Listen to clicks on the item value (DIV element): b.addEventListener("click", function(e) { var terms = searchBox.value.split(/\s+/); // Remove the current part of the input used for matching terms.pop(); // Insert the value for the autocomplete text field: terms.push(this.getElementsByTagName("input")[0].value); searchBox.value = terms.join(" "); // Move cursor position inside quotes/parenthesis if needed searchBox.focus(); if (searchBox.value[searchBox.value.length-1] === '"' || searchBox.value[searchBox.value.length-1] === ')') { searchBox.setSelectionRange(searchBox.value.length-1, searchBox.value.length-1); } // Close the list of autocompleted values closeAllLists(); }); a.appendChild(b); } } if (a.children.length > 0) { // By default, enter will select the first entry currentFocus = 0; addActive(a.children); } }); /*execute a function presses a key on the keyboard:*/ searchBox.addEventListener("keydown", function(e) { var x = document.getElementById(this.id + "autocomplete-list"); if (x) x = x.getElementsByTagName("div"); if (e.keyCode == 40) { // If the arrow DOWN key is pressed, increase the currentFocus variable: currentFocus++; addActive(x); } else if (e.keyCode == 38) { //up // If the arrow UP key is pressed, decrease the currentFocus variable: currentFocus--; /*and and make the current item more visible:*/ addActive(x); } else if (e.keyCode == 13) { // If the ENTER key is pressed: if (currentFocus > -1) { // Prevent the form from being submitted: e.preventDefault(); // Simulate a click on the "active" item: if (x) x[currentFocus].click(); currentFocus = -1; } } }); function addActive(x) { // Classify an item as "active": if (!x) return false; // Remove the "active" class on all items: removeActive(x); if (currentFocus >= x.length) currentFocus = 0; if (currentFocus < 0) currentFocus = (x.length - 1); // Add class "autocomplete-active": x[currentFocus].classList.add("autocomplete-active"); } function removeActive(x) { // Remove the "active" class from all autocomplete items: for (var i = 0; i < x.length; i++) { x[i].classList.remove("autocomplete-active"); } } function closeAllLists(elmnt) { // Close all autocomplete lists in the document, except the one passed as an argument: var x = document.getElementsByClassName("autocomplete-items"); for (var i = 0; i < x.length; i++) { if (elmnt != x[i] && elmnt != searchBox) { x[i].parentNode.removeChild(x[i]); } } } // Any other clicks in the document: document.addEventListener("click", function (e) { closeAllLists(e.target); }); } var autoList = [ { value: 'author:""', label: 'Author', match: 'author:"' }, { value: 'author:"^"', label: 'First Author', match: 'first author' }, { value: 'author:"^"', label: 'First Author', match: 'author:"^' }, { value: 'bibcode:""', label: 'Bibcode', desc: 'e.g. bibcode:1989ApJ...342L..71R', match: 'bibcode:"' }, { value: 'bibstem:""', label: 'Publication', desc: 'e.g. bibstem:ApJ', match: 'bibstem:"' }, { value: 'bibstem:""', label: 'Publication', desc: 'e.g. bibstem:ApJ', match: 'publication (bibstem)' }, { value: 'arXiv:', label: 'arXiv ID', match: 'arxiv:' }, { value: 'doi:', label: 'DOI', match: 'doi:' }, { value: 'full:""', label: 'Full text search', desc: 'title, abstract, and body', match: 'full:' }, { value: 'full:""', label: 'Full text search', desc: 'title, abstract, and body', match: 'fulltext' }, { value: 'full:""', label: 'Full text search', desc: 'title, abstract, and body', match: 'text' }, { value: 'year:', label: 'Year', match: 'year' }, { value: 'year:1999-2005', label: 'Year Range', desc: 'e.g. 1999-2005', match: 'year range' }, { value: 'aff:""', label: 'Affiliation', match: 'aff:' }, { value: 'abs:""', label: 'Search abstract + title + keywords', match: 'abs:' }, { value: 'database:astronomy', label: 'Limit to papers in the astronomy database', match: 'database:astronomy' }, { value: 'database:physics', label: 'Limit to papers in the physics database', match: 'database:physics' }, { value: 'title:""', label: 'Title', match: 'title:"' }, { value: 'orcid:', label: 'ORCiD identifier', match: 'orcid:' }, { value: 'object:', label: 'SIMBAD object (e.g. object:LMC)', match: 'object:' }, { value: 'property:refereed', label: 'Limit to refereed', desc: '(property:refereed)', match: 'refereed' }, { value: 'property:refereed', label: 'Limit to refereed', desc: '(property:refereed)', match: 'property:refereed' }, { value: 'property:notrefereed', label: 'Limit to non-refereed', desc: '(property:notrefereed)', match: 'property:notrefereed' }, { value: 'property:notrefereed', label: 'Limit to non-refereed', desc: '(property:notrefereed)', match: 'notrefereed' }, { value: 'property:eprint', label: 'Limit to eprints', desc: '(property:eprint)', match: 'eprint' }, { value: 'property:eprint', label: 'Limit to eprints', desc: '(property:eprint)', match: 'property:eprint' }, { value: 'property:openaccess', label: 'Limit to open access', desc: '(property:openaccess)', match: 'property:openaccess' }, { value: 'property:openaccess', label: 'Limit to open access', desc: '(property:openaccess)', match: 'openaccess' }, { value: 'doctype:software', label: 'Limit to software', desc: '(doctype:software)', match: 'software' }, { value: 'doctype:software', label: 'Limit to software', desc: '(doctype:software)', match: 'doctype:software' }, { value: 'property:inproceedings', label: 'Limit to papers in conference proceedings', desc: '(property:inproceedings)', match: 'proceedings' }, { value: 'property:inproceedings', label: 'Limit to papers in conference proceedings', desc: '(property:inproceedings)', match: 'property:inproceedings' }, { value: 'citations()', label: 'Citations', desc: 'Get papers citing your search result set', match: 'citations(' }, { value: 'references()', label: 'References', desc: 'Get papers referenced by your search result set', match: 'references(' }, { value: 'trending()', label: 'Trending', desc: 'Get papers most read by users who recently read your search result set', match: 'trending(' }, { value: 'reviews()', label: 'Review Articles', desc: 'Get most relevant papers that cite your search result set', match: 'reviews(' }, { value: 'useful()', label: 'Useful', desc: 'Get papers most frequently cited by your search result set', match: 'useful(' }, { value: 'similar()', label: 'Similar', desc: 'Get papers that have similar full text to your search result set', match: 'similar(' }, ]; // initiate the autocomplete function on the "q" element, and pass along the operators array as possible autocomplete values: inputBox = document.getElementById("q") if (inputBox) { inputBox.focus() // autofucs inputBox.setSelectionRange(inputBox.value.length, inputBox.value.length); // bring cursor to the end autocomplete(inputBox, autoList); } </script> <script> (function() { // turn off no-js if we have javascript document.documentElement.className = document.documentElement.className.replace("no-js", "js"); function getCookie(cname) { var name = cname + "="; var decodedCookie = decodeURIComponent(document.cookie); var ca = decodedCookie.split(';'); for (var i = 0; i < ca.length; i++) { var c = ca[i]; while (c.charAt(0) == ' ') { c = c.substring(1); } if (c.indexOf(name) == 0) { return c.substring(name.length, c.length); } } return ""; } (function() { // looks for the cookie, and sets true if its 'always' const coreCookie = getCookie('core') === 'always'; // only load bumblebee if we detect the core cookie and we are on abstract page if (coreCookie || (!(/^\/abs\//.test(document.location.pathname)) && !coreCookie)) { return; 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