Search | arXiv e-print repository

<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"/> <meta name="viewport" content="width=device-width, initial-scale=1"/>  <link rel="apple-touch-icon" sizes="180x180" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/apple-touch-icon.png"> <link rel="icon" type="image/png" sizes="32x32" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/favicon-32x32.png"> <link rel="icon" type="image/png" sizes="16x16" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/favicon-16x16.png"> <link rel="manifest" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/site.webmanifest"> <link rel="mask-icon" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/safari-pinned-tab.svg" color="#b31b1b"> <link rel="shortcut icon" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/favicon.ico"> <meta name="msapplication-TileColor" content="#b31b1b"> <meta name="msapplication-config" content="images/icons/browserconfig.xml"> <meta name="theme-color" content="#b31b1b">  <title>Search | arXiv e-print repository</title> <script defer src="https://static.arxiv.org/static/base/1.0.0a5/fontawesome-free-5.11.2-web/js/all.js"></script> <link rel="stylesheet" href="https://static.arxiv.org/static/base/1.0.0a5/css/arxivstyle.css" /> <script type="text/x-mathjax-config"> MathJax.Hub.Config({ messageStyle: "none", extensions: ["tex2jax.js"], jax: ["input/TeX", "output/HTML-CSS"], tex2jax: { inlineMath: [ ['$','$'], ["\$","\$"] ], displayMath: [ ['$$','$$'], ["\\[","\\]"] ], processEscapes: true, ignoreClass: '.*', processClass: 'mathjax.*' }, TeX: { extensions: ["AMSmath.js", "AMSsymbols.js", "noErrors.js"], noErrors: { inlineDelimiters: ["$","$"], multiLine: false, style: { "font-size": "normal", "border": "" } } }, "HTML-CSS": { availableFonts: ["TeX"] } }); </script> <script src='//static.arxiv.org/MathJax-2.7.3/MathJax.js'></script> <script src="https://static.arxiv.org/static/base/1.0.0a5/js/notification.js"></script> <link rel="stylesheet" href="https://static.arxiv.org/static/search/0.5.6/css/bulma-tooltip.min.css" /> <link rel="stylesheet" href="https://static.arxiv.org/static/search/0.5.6/css/search.css" /> <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha256-k2WSCIexGzOj3Euiig+TlR8gA0EmPjuc79OEeY5L45g=" crossorigin="anonymous"></script> <script src="https://static.arxiv.org/static/search/0.5.6/js/fieldset.js"></script> <style> radio#cf-customfield_11400 { display: none; } </style> </head> <body> <header><a href="#main-container" class="is-sr-only">Skip to main content</a>  <div class="attribution level is-marginless" role="banner"> <div class="level-left"> <a class="level-item" href="https://cornell.edu/"><img src="https://static.arxiv.org/static/base/1.0.0a5/images/cornell-reduced-white-SMALL.svg" alt="Cornell University" width="200" aria-label="logo" /></a> </div> <div class="level-right is-marginless"><p class="sponsors level-item is-marginless"><span id="support-ack-url">We gratefully acknowledge support from<br /> the Simons Foundation, <a href="https://info.arxiv.org/about/ourmembers.html">member institutions</a>, and all contributors. <a href="https://info.arxiv.org/about/donate.html">Donate</a></span></p></div> </div>  <div class="identity level is-marginless"> <div class="level-left"> <div class="level-item"> <a class="arxiv" href="https://arxiv.org/" aria-label="arxiv-logo"> <img src="https://static.arxiv.org/static/base/1.0.0a5/images/arxiv-logo-one-color-white.svg" aria-label="logo" alt="arxiv logo" width="85" style="width:85px;"/> </a> </div> </div> <div class="search-block level-right"> <form class="level-item mini-search" method="GET" action="https://arxiv.org/search"> <div class="field has-addons"> <div class="control"> <input class="input is-small" type="text" name="query" placeholder="Search..." aria-label="Search term or terms" /> <p class="help"><a href="https://info.arxiv.org/help">Help</a> | <a href="https://arxiv.org/search/advanced">Advanced Search</a></p> </div> <div class="control"> <div class="select is-small"> <select name="searchtype" aria-label="Field to search"> <option value="all" selected="selected">All fields</option> <option value="title">Title</option> <option value="author">Author</option> <option value="abstract">Abstract</option> <option value="comments">Comments</option> <option value="journal_ref">Journal reference</option> <option value="acm_class">ACM classification</option> <option value="msc_class">MSC classification</option> <option value="report_num">Report number</option> <option value="paper_id">arXiv identifier</option> <option value="doi">DOI</option> <option value="orcid">ORCID</option> <option value="author_id">arXiv author ID</option> <option value="help">Help pages</option> <option value="full_text">Full text</option> </select> </div> </div> <input type="hidden" name="source" value="header"> <button class="button is-small is-cul-darker">Search</button> </div> </form> </div> </div>  <div class="container"> <div class="user-tools is-size-7 has-text-right has-text-weight-bold" role="navigation" aria-label="User menu"> <a href="https://arxiv.org/login">Login</a> </div> </div> </header> <main class="container" id="main-container"> <div class="level is-marginless"> <div class="level-left"> <h1 class="title is-clearfix"> Showing 1–24 of 24 results for author: <span class="mathjax">Qasim, D</span> </h1> </div> <div class="level-right is-hidden-mobile">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> <div class="content"> <form method="GET" action="/search/" aria-role="search"> <div class="field has-addons-tablet"> <div class="control is-expanded"> <label for="query" class="hidden-label">Search term or terms</label> <input class="input is-medium" id="query" name="query" placeholder="Search term..." type="text" value="Qasim, D"> </div> <div class="select control is-medium"> <label class="is-hidden" for="searchtype">Field</label> <select class="is-medium" id="searchtype" name="searchtype"><option value="all">All fields</option><option value="title">Title</option><option selected value="author">Author(s)</option><option value="abstract">Abstract</option><option value="comments">Comments</option><option value="journal_ref">Journal reference</option><option value="acm_class">ACM classification</option><option value="msc_class">MSC classification</option><option value="report_num">Report number</option><option value="paper_id">arXiv identifier</option><option value="doi">DOI</option><option value="orcid">ORCID</option><option value="license">License (URI)</option><option value="author_id">arXiv author ID</option><option value="help">Help pages</option><option value="full_text">Full text</option></select> </div> <div class="control"> <button class="button is-link is-medium">Search</button> </div> </div> <div class="field"> <div class="control is-size-7"> <label class="radio"> <input checked id="abstracts-0" name="abstracts" type="radio" value="show"> Show abstracts </label> <label class="radio"> <input id="abstracts-1" name="abstracts" type="radio" value="hide"> Hide abstracts </label> </div> </div> <div class="is-clearfix" style="height: 2.5em"> <div class="is-pulled-right"> <a href="/search/advanced?terms-0-term=Qasim%2C+D&terms-0-field=author&size=50&order=-announced_date_first">Advanced Search</a> </div> </div> <input type="hidden" name="order" value="-announced_date_first"> <input type="hidden" name="size" value="50"> </form> <div class="level breathe-horizontal"> <div class="level-left"> <form method="GET" action="/search/"> <div style="display: none;"> <select id="searchtype" name="searchtype"><option value="all">All fields</option><option value="title">Title</option><option selected value="author">Author(s)</option><option value="abstract">Abstract</option><option value="comments">Comments</option><option value="journal_ref">Journal reference</option><option value="acm_class">ACM classification</option><option value="msc_class">MSC classification</option><option value="report_num">Report number</option><option value="paper_id">arXiv identifier</option><option value="doi">DOI</option><option value="orcid">ORCID</option><option value="license">License (URI)</option><option value="author_id">arXiv author ID</option><option value="help">Help pages</option><option value="full_text">Full text</option></select> <input id="query" name="query" type="text" value="Qasim, D"> <ul id="abstracts"><li><input checked id="abstracts-0" name="abstracts" type="radio" value="show"> <label for="abstracts-0">Show abstracts</label></li><li><input id="abstracts-1" name="abstracts" type="radio" value="hide"> <label for="abstracts-1">Hide abstracts</label></li></ul> </div> <div class="box field is-grouped is-grouped-multiline level-item"> <div class="control"> <span class="select is-small"> <select id="size" name="size"><option value="25">25</option><option selected value="50">50</option><option value="100">100</option><option value="200">200</option></select> </span> <label for="size">results per page</label>. </div> <div class="control"> <label for="order">Sort results by</label> <span class="select is-small"> <select id="order" name="order"><option selected value="-announced_date_first">Announcement date (newest first)</option><option value="announced_date_first">Announcement date (oldest first)</option><option value="-submitted_date">Submission date (newest first)</option><option value="submitted_date">Submission date (oldest first)</option><option value="">Relevance</option></select> </span> </div> <div class="control"> <button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.19651">arXiv:2411.19651</a> <span> [<a href="https://arxiv.org/pdf/2411.19651">pdf</a>, <a href="https://arxiv.org/format/2411.19651">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202451505">10.1051/0004-6361/202451505 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ice inventory towards the protostar Ced 110 IRS4 observed with the James Webb Space Telescope. Results from the ERS Ice Age program </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Rocha%2C+W+R+M">W. R. M. Rocha</a>, <a href="/search/?searchtype=author&query=McClure%2C+M+K">M. K. McClure</a>, <a href="/search/?searchtype=author&query=Sturm%2C+J+A">J. A. Sturm</a>, <a href="/search/?searchtype=author&query=Beck%2C+T+L">T. L. Beck</a>, <a href="/search/?searchtype=author&query=Smith%2C+Z+L">Z. L. Smith</a>, <a href="/search/?searchtype=author&query=Dickinson%2C+H">H. Dickinson</a>, <a href="/search/?searchtype=author&query=Sun%2C+F">F. Sun</a>, <a href="/search/?searchtype=author&query=Egami%2C+E">E. Egami</a>, <a href="/search/?searchtype=author&query=Boogert%2C+A+C+A">A. C. A. Boogert</a>, <a href="/search/?searchtype=author&query=Fraser%2C+H+J">H. J. Fraser</a>, <a href="/search/?searchtype=author&query=Dartois%2C+E">E. Dartois</a>, <a href="/search/?searchtype=author&query=Jimenez-Serra%2C+I">I. Jimenez-Serra</a>, <a href="/search/?searchtype=author&query=Noble%2C+J+A">J. A. Noble</a>, <a href="/search/?searchtype=author&query=Bergner%2C+J">J. Bergner</a>, <a href="/search/?searchtype=author&query=Caselli%2C+P">P. Caselli</a>, <a href="/search/?searchtype=author&query=Charnley%2C+S+B">S. B. Charnley</a>, <a href="/search/?searchtype=author&query=Chiar%2C+J">J. Chiar</a>, <a href="/search/?searchtype=author&query=Chu%2C+L">L. Chu</a>, <a href="/search/?searchtype=author&query=Cooke%2C+I">I. Cooke</a>, <a href="/search/?searchtype=author&query=Crouzet%2C+N">N. Crouzet</a>, <a href="/search/?searchtype=author&query=van+Dishoeck%2C+E+F">E. F. van Dishoeck</a>, <a href="/search/?searchtype=author&query=Drozdovskaya%2C+M+N">M. N. Drozdovskaya</a>, <a href="/search/?searchtype=author&query=Garrod%2C+R">R. Garrod</a>, <a href="/search/?searchtype=author&query=Harsono%2C+D">D. Harsono</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S. Ioppolo</a> , et al. (15 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.19651v1-abstract-short" style="display: inline;"> This work focuses on the ice features toward the binary protostellar system Ced 110 IRS 4A and 4B, and observed with JWST as part of the Early Release Science Ice Age collaboration. We aim to explore the JWST observations of the binary protostellar system Ced~110~IRS4A and IRS4B to unveil and quantify the ice inventories toward these sources. We compare the ice abundances with those found for the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.19651v1-abstract-full').style.display = 'inline'; document.getElementById('2411.19651v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.19651v1-abstract-full" style="display: none;"> This work focuses on the ice features toward the binary protostellar system Ced 110 IRS 4A and 4B, and observed with JWST as part of the Early Release Science Ice Age collaboration. We aim to explore the JWST observations of the binary protostellar system Ced~110~IRS4A and IRS4B to unveil and quantify the ice inventories toward these sources. We compare the ice abundances with those found for the same molecular cloud. The analysis is performed by fitting or comparing laboratory infrared spectra of ices to the observations. Spectral fits are carried out with the ENIIGMA fitting tool that searches for the best fit. For Ced~110~IRS4B, we detected the major ice species H$_2$O, CO, CO$_2$ and NH$_3$. All species are found in a mixture except for CO and CO$_2$, which have both mixed and pure ice components. In the case of Ced~110~IRS4A, we detected the same major species as in Ced~110~IRS4B, as well as the following minor species CH$_4$, SO$_2$, CH$_3$OH, OCN$^-$, NH$_4^+$ and HCOOH. Tentative detection of N$_2$O ice (7.75~$渭$m), forsterite dust (11.2~$渭$m) and CH$_3^+$ gas emission (7.18~$渭$m) in the primary source are also presented. Compared with the two lines of sight toward background stars in the Chameleon I molecular cloud, the protostar has similar ice abundances, except in the case of the ions that are higher in IRS4A. The clearest differences are the absence of the 7.2 and 7.4~$渭$m absorption features due to HCOO$^-$ and icy complex organic molecules in IRS4A and evidence of thermal processing in both IRS4A and IRS4B as probed by the CO$_2$ ice features. We conclude that the binary protostellar system Ced~110~IRS4A and IRS4B has a large inventory of icy species. The similar ice abundances in comparison to the starless regions in the same molecular cloud suggest that the chemical conditions of the protostar were set at earlier stages in the molecular cloud. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.19651v1-abstract-full').style.display = 'none'; document.getElementById('2411.19651v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">33 pages, 19 Figures. Accepted for publication in Astronomy & Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 693, A288 (2025) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.08117">arXiv:2409.08117</a> <span> [<a href="https://arxiv.org/pdf/2409.08117">pdf</a>, <a href="https://arxiv.org/format/2409.08117">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> </div> <p class="title is-5 mathjax"> JWST ice band profiles reveal mixed ice compositions in the HH 48 NE disk </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Bergner%2C+J+B">Jennifer B. Bergner</a>, <a href="/search/?searchtype=author&query=Sturm%2C+J+A">J. A. Sturm</a>, <a href="/search/?searchtype=author&query=Piacentino%2C+E+L">Elettra L. Piacentino</a>, <a href="/search/?searchtype=author&query=McClure%2C+M+K">M. K. McClure</a>, <a href="/search/?searchtype=author&query=Oberg%2C+K+I">Karin I. Oberg</a>, <a href="/search/?searchtype=author&query=Boogert%2C+A+C+A">A. C. A. Boogert</a>, <a href="/search/?searchtype=author&query=Dartois%2C+E">E. Dartois</a>, <a href="/search/?searchtype=author&query=Drozdovskaya%2C+M+N">M. N. Drozdovskaya</a>, <a href="/search/?searchtype=author&query=Fraser%2C+H+J">H. J. Fraser</a>, <a href="/search/?searchtype=author&query=Harsono%2C+D">Daniel Harsono</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">Sergio Ioppolo</a>, <a href="/search/?searchtype=author&query=Law%2C+C+J">Charles J. Law</a>, <a href="/search/?searchtype=author&query=Lis%2C+D+C">Dariusz C. Lis</a>, <a href="/search/?searchtype=author&query=McGuire%2C+B+A">Brett A. McGuire</a>, <a href="/search/?searchtype=author&query=Melnick%2C+G+J">Gary J. Melnick</a>, <a href="/search/?searchtype=author&query=Noble%2C+J+A">Jennifer A. Noble</a>, <a href="/search/?searchtype=author&query=Palumbo%2C+M+E">M. E. Palumbo</a>, <a href="/search/?searchtype=author&query=Pendleton%2C+Y+J">Yvonne J. Pendleton</a>, <a href="/search/?searchtype=author&query=Perotti%2C+G">Giulia Perotti</a>, <a href="/search/?searchtype=author&query=Qasim%2C+D">Danna Qasim</a>, <a href="/search/?searchtype=author&query=Rocha%2C+W+R+M">W. R. M. Rocha</a>, <a href="/search/?searchtype=author&query=van+Dishoeck%2C+E+F">E. F. van Dishoeck</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.08117v1-abstract-short" style="display: inline;"> Planet formation is strongly influenced by the composition and distribution of volatiles within protoplanetary disks. With JWST, it is now possible to obtain direct observational constraints on disk ices, as recently demonstrated by the detection of ice absorption features towards the edge-on HH 48 NE disk as part of the Ice Age Early Release Science program. Here, we introduce a new radiative tra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.08117v1-abstract-full').style.display = 'inline'; document.getElementById('2409.08117v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.08117v1-abstract-full" style="display: none;"> Planet formation is strongly influenced by the composition and distribution of volatiles within protoplanetary disks. With JWST, it is now possible to obtain direct observational constraints on disk ices, as recently demonstrated by the detection of ice absorption features towards the edge-on HH 48 NE disk as part of the Ice Age Early Release Science program. Here, we introduce a new radiative transfer modeling framework designed to retrieve the composition and mixing status of disk ices using their band profiles, and apply it to interpret the H2O, CO2, and CO ice bands observed towards the HH 48 NE disk. We show that the ices are largely present as mixtures, with strong evidence for CO trapping in both H2O and CO2 ice. The HH 48 NE disk ice composition (pure vs. polar vs. apolar fractions) is markedly different from earlier protostellar stages, implying thermal and/or chemical reprocessing during the formation or evolution of the disk. We infer low ice-phase C/O ratios around 0.1 throughout the disk, and also demonstrate that the mixing and entrapment of disk ices can dramatically affect the radial dependence of the C/O ratio. It is therefore imperative that realistic disk ice compositions are considered when comparing planetary compositions with potential formation scenarios, which will fortunately be possible for an increasing number of disks with JWST. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.08117v1-abstract-full').style.display = 'none'; document.getElementById('2409.08117v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted to ApJ. 24 pages, 15 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.04760">arXiv:2401.04760</a> <span> [<a href="https://arxiv.org/pdf/2401.04760">pdf</a>, <a href="https://arxiv.org/format/2401.04760">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202347832">10.1051/0004-6361/202347832 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A deep search for large complex organic species toward IRAS16293-2422 B at 3 mm with ALMA </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Nazari%2C+P">P. Nazari</a>, <a href="/search/?searchtype=author&query=Cheung%2C+J+S+Y">J. S. Y. Cheung</a>, <a href="/search/?searchtype=author&query=Asensio%2C+J+F">J. Ferrer Asensio</a>, <a href="/search/?searchtype=author&query=Murillo%2C+N+M">N. M. Murillo</a>, <a href="/search/?searchtype=author&query=van+Dishoeck%2C+E+F">E. F. van Dishoeck</a>, <a href="/search/?searchtype=author&query=J%C3%B8rgensen%2C+J+K">J. K. J酶rgensen</a>, <a href="/search/?searchtype=author&query=Bourke%2C+T+L">T. L. Bourke</a>, <a href="/search/?searchtype=author&query=Chuang%2C+K+-">K. -J. Chuang</a>, <a href="/search/?searchtype=author&query=Drozdovskaya%2C+M+N">M. N. Drozdovskaya</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">G. Fedoseev</a>, <a href="/search/?searchtype=author&query=Garrod%2C+R+T">R. T. Garrod</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S. Ioppolo</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">H. Linnartz</a>, <a href="/search/?searchtype=author&query=McGuire%2C+B+A">B. A. McGuire</a>, <a href="/search/?searchtype=author&query=M%C3%BCller%2C+H+S+P">H. S. P. M眉ller</a>, <a href="/search/?searchtype=author&query=Qasim%2C+D">D. Qasim</a>, <a href="/search/?searchtype=author&query=Wampfler%2C+S+F">S. F. Wampfler</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2401.04760v1-abstract-short" style="display: inline;"> Complex organic molecules (COMs) have been detected ubiquitously in protostellar systems. However, at shorter wavelengths (~0.8mm) it is more difficult to detect larger molecules than at longer wavelengths (~3mm) because of the increase of millimeter dust opacity, line confusion, and unfavorable partition function. We aim to search for large molecules (>8 atoms) in the ALMA Band 3 spectrum of IRAS… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.04760v1-abstract-full').style.display = 'inline'; document.getElementById('2401.04760v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.04760v1-abstract-full" style="display: none;"> Complex organic molecules (COMs) have been detected ubiquitously in protostellar systems. However, at shorter wavelengths (~0.8mm) it is more difficult to detect larger molecules than at longer wavelengths (~3mm) because of the increase of millimeter dust opacity, line confusion, and unfavorable partition function. We aim to search for large molecules (>8 atoms) in the ALMA Band 3 spectrum of IRAS 16293-2422 B. We search for more than 70 molecules and identify as many lines as possible in the spectrum. The spectral settings were set to specifically target three-carbon species such as propanol and glycerol. We identify lines of 31 molecules including many oxygen-bearing COMs such as CH3OH and c-C2H4O and a few nitrogen- and sulfur-bearing ones such as HOCH2CN and CH3SH. The largest detected molecules are gGg-(CH2OH)2 and CH3COCH3. We do not detect glycerol or propanol but provide upper limits for them which are in line with previous laboratory and observational studies. The line density in Band 3 is only ~2.5 times lower in frequency space than in Band 7. From the detected lines in Band 3 at a $\gtrsim 6蟽$ level, ~25-30% of them could not be identified indicating the need for more laboratory data of rotational spectra. We find similar column densities and column density ratios of COMs (within a factor ~2) between Band 3 and Band 7. The effect of dust optical depth for IRAS 16293-2422 B at an off-source location on column densities and column density ratios is minimal. Moreover, for warm protostars, long wavelength spectra are not only crowded, but also take longer integration times to reach the same sensitivity limit. The 3mm search has not yet resulted in detection of larger and more complex molecules in warm sources. A full deep ALMA Band 2-3 (i.e., 3-4 mm) survey is needed to assess whether low frequency data have the potential to reveal more complex molecules in warm sources. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.04760v1-abstract-full').style.display = 'none'; document.getElementById('2401.04760v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 686, A59 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.07817">arXiv:2309.07817</a> <span> [<a href="https://arxiv.org/pdf/2309.07817">pdf</a>, <a href="https://arxiv.org/format/2309.07817">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> A JWST inventory of protoplanetary disk ices: The edge-on protoplanetary disk HH 48 NE, seen with the Ice Age ERS program </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Sturm%2C+J+A">J. A. Sturm</a>, <a href="/search/?searchtype=author&query=McClure%2C+M+K">M. K. McClure</a>, <a href="/search/?searchtype=author&query=Beck%2C+T+L">T. L. Beck</a>, <a href="/search/?searchtype=author&query=Harsono%2C+D">D. Harsono</a>, <a href="/search/?searchtype=author&query=Bergner%2C+J+B">J. B. Bergner</a>, <a href="/search/?searchtype=author&query=Dartois%2C+E">E. Dartois</a>, <a href="/search/?searchtype=author&query=Boogert%2C+A+C+A">A. C. A. Boogert</a>, <a href="/search/?searchtype=author&query=Chiar%2C+J+E">J. E. Chiar</a>, <a href="/search/?searchtype=author&query=Cordiner%2C+M+A">M. A. Cordiner</a>, <a href="/search/?searchtype=author&query=Drozdovskaya%2C+M+N">M. N. Drozdovskaya</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S. Ioppolo</a>, <a href="/search/?searchtype=author&query=Law%2C+C+J">C. J. Law</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">H. Linnartz</a>, <a href="/search/?searchtype=author&query=Lis%2C+D+C">D. C. Lis</a>, <a href="/search/?searchtype=author&query=Melnick%2C+G+J">G. J. Melnick</a>, <a href="/search/?searchtype=author&query=McGuire%2C+B+A">B. A. McGuire</a>, <a href="/search/?searchtype=author&query=Noble%2C+J+A">J. A. Noble</a>, <a href="/search/?searchtype=author&query=%C3%96berg%2C+K+I">K. I. 脰berg</a>, <a href="/search/?searchtype=author&query=Palumbo%2C+M+E">M. E. Palumbo</a>, <a href="/search/?searchtype=author&query=Pendleton%2C+Y+J">Y. J. Pendleton</a>, <a href="/search/?searchtype=author&query=Perotti%2C+G">G. Perotti</a>, <a href="/search/?searchtype=author&query=Pontoppidan%2C+K+M">K. M. Pontoppidan</a>, <a href="/search/?searchtype=author&query=Qasim%2C+D">D. Qasim</a>, <a href="/search/?searchtype=author&query=Rocha%2C+W+R+M">W. R. M. Rocha</a>, <a href="/search/?searchtype=author&query=Terada%2C+H">H. Terada</a> , et al. (2 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2309.07817v1-abstract-short" style="display: inline;"> Ices are the main carriers of volatiles in protoplanetary disks and are crucial to our understanding of the chemistry that ultimately sets the organic composition of planets. The ERS program Ice Age on the JWST follows the ice evolution through all stages of star and planet formation. JWST/NIRSpec observations of the edge-on Class II protoplanetary disk HH~48~NE reveal spatially resolved absorptio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.07817v1-abstract-full').style.display = 'inline'; document.getElementById('2309.07817v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.07817v1-abstract-full" style="display: none;"> Ices are the main carriers of volatiles in protoplanetary disks and are crucial to our understanding of the chemistry that ultimately sets the organic composition of planets. The ERS program Ice Age on the JWST follows the ice evolution through all stages of star and planet formation. JWST/NIRSpec observations of the edge-on Class II protoplanetary disk HH~48~NE reveal spatially resolved absorption features of the major ice components H$_2$O, CO$_2$, CO, and multiple weaker signatures from less abundant ices NH$_3$, OCN$^-$, and OCS. Isotopologue $^{13}$CO$_2$ ice has been detected for the first time in a protoplanetary disk. Since multiple complex light paths contribute to the observed flux, the ice absorption features are filled in by ice-free scattered light. The $^{12}$CO$_2$/$^{13}$CO$_2$ ratio of 14 implies that the $^{12}$CO$_2$ feature is saturated, without the flux approaching 0, indicative of a very high CO$_2$ column density on the line of sight, and a corresponding abundance with respect to hydrogen that is higher than ISM values by a factor of at least a few. Observations of rare isotopologues are crucial, as we show that the $^{13}$CO$_2$ observation allows us to determine the column density of CO$_2$ to be at an order of magnitude higher than the lower limit directly inferred from the observed optical depth. Radial variations in ice abundance, e.g., snowlines, are significantly modified since all observed photons have passed through the full radial extent of the disk. CO ice is observed at perplexing heights in the disk, extending to the top of the CO-emitting gas layer. We argue that the most likely interpretation is that we observe some CO ice at high temperatures, trapped in less volatile ices like H$_2$O and CO$_2$. Future radiative transfer models will be required to constrain the implications on our current understanding of disk physics and chemistry. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.07817v1-abstract-full').style.display = 'none'; document.getElementById('2309.07817v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 8 figures, accepted for publication in A&A</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2301.09140">arXiv:2301.09140</a> <span> [<a href="https://arxiv.org/pdf/2301.09140">pdf</a>, <a href="https://arxiv.org/format/2301.09140">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41550-022-01875-w">10.1038/s41550-022-01875-w <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> An Ice Age JWST inventory of dense molecular cloud ices </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=McClure%2C+M+K">M. K. McClure</a>, <a href="/search/?searchtype=author&query=Rocha%2C+W+R+M">W. R. M. Rocha</a>, <a href="/search/?searchtype=author&query=Pontoppidan%2C+K+M">K. M. Pontoppidan</a>, <a href="/search/?searchtype=author&query=Crouzet%2C+N">N. Crouzet</a>, <a href="/search/?searchtype=author&query=Chu%2C+L+E+U">L. E. U. Chu</a>, <a href="/search/?searchtype=author&query=Dartois%2C+E">E. Dartois</a>, <a href="/search/?searchtype=author&query=Lamberts%2C+T">T. Lamberts</a>, <a href="/search/?searchtype=author&query=Noble%2C+J+A">J. A. Noble</a>, <a href="/search/?searchtype=author&query=Pendleton%2C+Y+J">Y. J. Pendleton</a>, <a href="/search/?searchtype=author&query=Perotti%2C+G">G. Perotti</a>, <a href="/search/?searchtype=author&query=Qasim%2C+D">D. Qasim</a>, <a href="/search/?searchtype=author&query=Rachid%2C+M+G">M. G. Rachid</a>, <a href="/search/?searchtype=author&query=Smith%2C+Z+L">Z. L. Smith</a>, <a href="/search/?searchtype=author&query=Sun%2C+F">Fengwu Sun</a>, <a href="/search/?searchtype=author&query=Beck%2C+T+L">Tracy L Beck</a>, <a href="/search/?searchtype=author&query=Boogert%2C+A+C+A">A. C. A. Boogert</a>, <a href="/search/?searchtype=author&query=Brown%2C+W+A">W. A. Brown</a>, <a href="/search/?searchtype=author&query=Caselli%2C+P">P. Caselli</a>, <a href="/search/?searchtype=author&query=Charnley%2C+S+B">S. B. Charnley</a>, <a href="/search/?searchtype=author&query=Cuppen%2C+H+M">Herma M. Cuppen</a>, <a href="/search/?searchtype=author&query=Dickinson%2C+H">H. Dickinson</a>, <a href="/search/?searchtype=author&query=Drozdovskaya%2C+M+N">M. N. Drozdovskaya</a>, <a href="/search/?searchtype=author&query=Egami%2C+E">E. Egami</a>, <a href="/search/?searchtype=author&query=Erkal%2C+J">J. Erkal</a>, <a href="/search/?searchtype=author&query=Fraser%2C+H">H. Fraser</a> , et al. (17 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2301.09140v1-abstract-short" style="display: inline;"> Icy grain mantles are the main reservoir of the volatile elements that link chemical processes in dark, interstellar clouds with the formation of planets and composition of their atmospheres. The initial ice composition is set in the cold, dense parts of molecular clouds, prior to the onset of star formation. With the exquisite sensitivity of JWST, this critical stage of ice evolution is now acces… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.09140v1-abstract-full').style.display = 'inline'; document.getElementById('2301.09140v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2301.09140v1-abstract-full" style="display: none;"> Icy grain mantles are the main reservoir of the volatile elements that link chemical processes in dark, interstellar clouds with the formation of planets and composition of their atmospheres. The initial ice composition is set in the cold, dense parts of molecular clouds, prior to the onset of star formation. With the exquisite sensitivity of JWST, this critical stage of ice evolution is now accessible for detailed study. Here we show the first results of the Early Release Science program "Ice Age" that reveal the rich composition of these dense cloud ices. Weak ices, including, $^{13}$CO$_2$, OCN$^-$, $^{13}$CO, OCS, and COMs functional groups are now detected along two pre-stellar lines of sight. The $^{12}$CO$_2$ ice profile indicates modest growth of the icy grains. Column densities of the major and minor ice species indicate that ices contribute between 2 and 19% of the bulk budgets of the key C, O, N, and S elements. Our results suggest that the formation of simple and complex molecules could begin early in a water-ice rich environment. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.09140v1-abstract-full').style.display = 'none'; document.getElementById('2301.09140v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">To appear in Nature Astronomy on January 23rd, 2023. 33 pages, 16 figures, 3 tables; includes extended and supplemental data sections. Part of the JWST Ice Age Early Release Science program's science enabling products. Enhanced spectra downloadable on Zenodo at the following DOI: 10.5281/zenodo.7501239</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2301.04103">arXiv:2301.04103</a> <span> [<a href="https://arxiv.org/pdf/2301.04103">pdf</a>, <a href="https://arxiv.org/format/2301.04103">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Geophysics">physics.geo-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acsearthspacechem.2c00274">10.1021/acsearthspacechem.2c00274 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Meteorite Parent Body Aqueous Alteration Simulations of Interstellar Residue Analogs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Qasim%2C+D">Danna Qasim</a>, <a href="/search/?searchtype=author&query=McLain%2C+H+L">Hannah L. McLain</a>, <a href="/search/?searchtype=author&query=Aponte%2C+J+C">Jose C. Aponte</a>, <a href="/search/?searchtype=author&query=Glavin%2C+D+P">Daniel P. Glavin</a>, <a href="/search/?searchtype=author&query=Dworkin%2C+J+P">Jason P. Dworkin</a>, <a href="/search/?searchtype=author&query=Materese%2C+C+K">Christopher K. Materese</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2301.04103v2-abstract-short" style="display: inline;"> Some families of carbonaceous chondrites are rich in prebiotic organics that may have contributed to the origin of life on Earth and elsewhere. However, the formation and chemical evolution of complex soluble organic molecules from interstellar precursors under relevant parent body conditions has not been thoroughly investigated. In this study, we approach this topic by simulating meteorite parent… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.04103v2-abstract-full').style.display = 'inline'; document.getElementById('2301.04103v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2301.04103v2-abstract-full" style="display: none;"> Some families of carbonaceous chondrites are rich in prebiotic organics that may have contributed to the origin of life on Earth and elsewhere. However, the formation and chemical evolution of complex soluble organic molecules from interstellar precursors under relevant parent body conditions has not been thoroughly investigated. In this study, we approach this topic by simulating meteorite parent body aqueous alteration of interstellar residue analogs. The distributions of amines and amino acids are qualitatively and quantitatively investigated and linked to closing the gap between interstellar and meteoritic prebiotic organic abundances. We find that the abundance trend of methylamine > ethylamine> glycine > serine > alanine > \b{eta}-alanine does not change from pre- to post-aqueous alteration, suggesting that certain cloud conditions have an influential role on the distributions of interstellar-inherited meteoritic organics. However, the abundances for most of the amines and amino acids studied here varied by about 2-fold when aqueously processed for 7 days at 125 掳C, and the changes in the 伪- to \b{eta}-alanine ratio were consistent with those of aqueously altered carbonaceous chondrites, pointing to an influential role of meteorite parent body processing on the distributions of interstellar-inherited meteoritic organics. We detected higher abundances of 伪- over \b{eta}-alanine, which is opposite to what is typically observed in aqueously altered carbonaceous chondrites; these results may be explained by at least the lack of minerals and insoluble organic matter-relevant materials in the experiments. The high abundance of volatile amines in the non-aqueously altered samples suggests that these types of interstellar volatiles can be efficiently transferred to asteroids and comets, supporting the idea of the presence of interstellar organics in solar system objects. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.04103v2-abstract-full').style.display = 'none'; document.getElementById('2301.04103v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">see overview https://www.nasa.gov/feature/goddard/2023/nasa-scientists-study-life-origins-by-simulating-a-mini-cosmic-evolution/</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Published in ACS Earth and Space Chemistry Jan. 2023; Supporting Info available at https://pubs.acs.org/doi/10.1021/acsearthspacechem.2c00274?goto=supporting-info </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2204.13212">arXiv:2204.13212</a> <span> [<a href="https://arxiv.org/pdf/2204.13212">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac602b">10.3847/1538-4357/ac602b <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Radiation-induced D/H Exchange Rate Constants in Aliphatics Embedded in Water Ice </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Qasim%2C+D">Danna Qasim</a>, <a href="/search/?searchtype=author&query=Hudson%2C+R+L">Reggie L. Hudson</a>, <a href="/search/?searchtype=author&query=Materese%2C+C+K">Christopher K. Materese</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2204.13212v1-abstract-short" style="display: inline;"> Gas-phase and solid-state chemistry in low-temperature interstellar clouds and cores leads to a D/H enhancement in interstellar ices, which is eventually inherited by comets, meteorites, and even planetary satellites. Hence, the D/ H ratio has been widely used as a tracer for the origins of extraterrestrial chemistry. However, the D/H ratio can also be influenced by cosmic rays, which are ubiquito… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.13212v1-abstract-full').style.display = 'inline'; document.getElementById('2204.13212v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.13212v1-abstract-full" style="display: none;"> Gas-phase and solid-state chemistry in low-temperature interstellar clouds and cores leads to a D/H enhancement in interstellar ices, which is eventually inherited by comets, meteorites, and even planetary satellites. Hence, the D/ H ratio has been widely used as a tracer for the origins of extraterrestrial chemistry. However, the D/H ratio can also be influenced by cosmic rays, which are ubiquitous and can penetrate even dense interstellar molecular cores. The effects of such high-energy radiation on deuterium fractionation have not been studied in a quantitative manner. In this study, we present rate constants for radiation-induced D-to-H exchange for fully deuterated small (1-2 C) hydrocarbons embedded in H2O ice at 20 K and H-to-D exchange for the protiated forms of these molecules in D2O ice at 20 K. We observed larger rate constants for H-to-D exchange in the D2O ice versus D-to-H exchange in H2O ice, which we have attributed to the greater bond strength of C-D versus C-H. We find that the H-to-D exchange rate constants are smaller for protiated methane than ethane, in agreement with bond energies from the literature. We are unable to obtain rate constants for the unsaturated and reactive hydrocarbons ethylene and acetylene. Interpretation of the rate constants suggest that D/H exchange products are formed in abundance alongside radiolysis products. We discuss how our quantitative and qualitative data can be used to interpret the D/ H ratios of aliphatic compounds observed throughout space. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.13212v1-abstract-full').style.display = 'none'; document.getElementById('2204.13212v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal, April 2022 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2112.09230">arXiv:2112.09230</a> <span> [<a href="https://arxiv.org/pdf/2112.09230">pdf</a>, <a href="https://arxiv.org/format/2112.09230">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202142414">10.1051/0004-6361/202142414 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Methoxymethanol Formation Starting from CO-Hydrogenation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=He%2C+J">Jiao He</a>, <a href="/search/?searchtype=author&query=Simons%2C+M">Mart Simons</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">Gleb Fedoseev</a>, <a href="/search/?searchtype=author&query=Chuang%2C+K">Ko-Ju Chuang</a>, <a href="/search/?searchtype=author&query=Qasim%2C+D">Danna Qasim</a>, <a href="/search/?searchtype=author&query=Lamberts%2C+T">Thanja Lamberts</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">Sergio Ioppolo</a>, <a href="/search/?searchtype=author&query=McGuire%2C+B+A">Brett A. McGuire</a>, <a href="/search/?searchtype=author&query=Cuppen%2C+H">Herma Cuppen</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">Harold Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2112.09230v1-abstract-short" style="display: inline;"> Methoxymethanol (CH3OCH2OH, MM) has been identified through gas-phase signatures in both high- and low-mass star-forming regions. This molecule is expected to form upon hydrogen addition and abstraction reactions in CO-rich ice through radical recombination of CO hydrogenation products. The goal of this work is to investigate experimentally and theoretically the most likely solid-state MM reaction… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2112.09230v1-abstract-full').style.display = 'inline'; document.getElementById('2112.09230v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2112.09230v1-abstract-full" style="display: none;"> Methoxymethanol (CH3OCH2OH, MM) has been identified through gas-phase signatures in both high- and low-mass star-forming regions. This molecule is expected to form upon hydrogen addition and abstraction reactions in CO-rich ice through radical recombination of CO hydrogenation products. The goal of this work is to investigate experimentally and theoretically the most likely solid-state MM reaction channel -- the recombination of CH2OH and CH3O radicals -- for dark interstellar cloud conditions and to compare the formation efficiency with that of other species that were shown to form along the CO-hydrogenation line. Hydrogen atoms and CO or H2CO molecules are co-deposited on top of the predeposited H2O ice to mimic the conditions associated with the beginning of 'rapid' CO freeze-out. Quadrupole mass spectrometry is used to analyze the gas-phase COM composition following a temperature programmed desorption. Monte Carlo simulations are used for an astrochemical model comparing the MM formation efficiency with that of other COMs. Unambiguous detection of newly formed MM has been possible both in CO+H and H2CO+H experiments. The resulting abundance of MM with respect to CH3OH is about 0.05, which is about 6 times less than the value observed toward NGC 6334I and about 3 times less than the value reported for IRAS 16293B. The results of astrochemical simulations predict a similar value for the MM abundance with respect to CH3OH factors ranging between 0.06 to 0.03. We find that MM is formed by co-deposition of CO and H2CO with H atoms through the recombination of CH2OH and CH3O radicals. In both the experimental and modeling studies, the efficiency of this channel alone is not sufficient to explain the observed abundance of MM. These results indicate an incomplete knowledge of the reaction network or the presence of alternative solid-state or gas-phase formation mechanisms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2112.09230v1-abstract-full').style.display = 'none'; document.getElementById('2112.09230v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 December, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 8 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 659, A65 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2111.08548">arXiv:2111.08548</a> <span> [<a href="https://arxiv.org/pdf/2111.08548">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac3834">10.3847/1538-4357/ac3834 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Hydrogenation of accreting C-atoms and CO molecules -- simulating ketene and acetaldehyde formation under dark and translucent cloud conditions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Fedoseev%2C+G">Gleb Fedoseev</a>, <a href="/search/?searchtype=author&query=Qasim%2C+D">Danna Qasim</a>, <a href="/search/?searchtype=author&query=Chuang%2C+K">Ko-Ju Chuang</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">Sergio Ioppolo</a>, <a href="/search/?searchtype=author&query=Lamberts%2C+T">Thanja Lamberts</a>, <a href="/search/?searchtype=author&query=van+Dishoeck%2C+E+F">Ewine F. van Dishoeck</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">Harold Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2111.08548v1-abstract-short" style="display: inline;"> Simple and complex organic molecules (COMs) are observed along different phases of star and planet formation and have been successfully identified in prestellar environments such as dark and translucent clouds. Yet the picture of organic molecule formation at those earliest stages of star formation is not complete and an important reason is the lack of specific laboratory experiments that simulate… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.08548v1-abstract-full').style.display = 'inline'; document.getElementById('2111.08548v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2111.08548v1-abstract-full" style="display: none;"> Simple and complex organic molecules (COMs) are observed along different phases of star and planet formation and have been successfully identified in prestellar environments such as dark and translucent clouds. Yet the picture of organic molecule formation at those earliest stages of star formation is not complete and an important reason is the lack of specific laboratory experiments that simulate carbon atom addition reactions on icy surfaces of interstellar grains. Here we present experiments in which CO molecules as well as C- and H-atoms are co-deposited with H$_2$O molecules on a 10 K surface mimicking the ongoing formation of an "H$_2$O-rich" ice mantle. To simulate the effect of impacting C-atoms and resulting surface reactions with ice components, a specialized C-atom beam source is used, implemented on SURFRESIDE$^3$, an UHV cryogenic setup. Formation of ketene (CH$_2$CO) in the solid state is observed "in situ" by means of reflection absorption IR spectroscopy. C$^1$$^8$O and D isotope labelled experiments are performed to further validate the formation of ketene. Data analysis supports that CH$_2$CO is formed through C-atom addition to a CO-molecule, followed by successive hydrogenation transferring the formed :CCO into ketene. Efficient formation of ketene is in line with the absence of an activation barrier in C+CO reaction reported in the literature. We also discuss and provide experimental evidence for the formation of acetaldehyde (CH$_3$CHO) and possible formation of ethanol (CH$_3$CH$_2$OH), two COM derivatives of CH$_2$CO hydrogenation. The underlying reaction network is presented and the astrochemical implications of the derived pathways are discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.08548v1-abstract-full').style.display = 'none'; document.getElementById('2111.08548v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 November, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted by ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2110.15887">arXiv:2110.15887</a> <span> [<a href="https://arxiv.org/pdf/2110.15887">pdf</a>, <a href="https://arxiv.org/format/2110.15887">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acs.jpclett.1c02760">10.1021/acs.jpclett.1c02760 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Carbon Atom Reactivity with Amorphous Solid Water: H$_2$O Catalyzed Formation of H$_2$CO </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Molpeceres%2C+G">Germ谩n Molpeceres</a>, <a href="/search/?searchtype=author&query=K%C3%A4stner%2C+J">Johannes K盲stner</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">Gleb Fedoseev</a>, <a href="/search/?searchtype=author&query=Qasim%2C+D">Danna Qasim</a>, <a href="/search/?searchtype=author&query=Sch%C3%B6mig%2C+R">Richard Sch枚mig</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">Harold Linnartz</a>, <a href="/search/?searchtype=author&query=Lamberts%2C+T">Thanja Lamberts</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2110.15887v1-abstract-short" style="display: inline;"> We report new computational and experimental evidence of an efficient and astrochemically relevant formation route to formaldehyde (H$_2$CO). This simplest carbonylic compound is central to the formation of complex organics in cold interstellar clouds, and is generally regarded to be formed by the hydrogenation of solid-state carbon monoxide. We demonstrate H$_2$CO formation via the reaction of ca… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.15887v1-abstract-full').style.display = 'inline'; document.getElementById('2110.15887v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.15887v1-abstract-full" style="display: none;"> We report new computational and experimental evidence of an efficient and astrochemically relevant formation route to formaldehyde (H$_2$CO). This simplest carbonylic compound is central to the formation of complex organics in cold interstellar clouds, and is generally regarded to be formed by the hydrogenation of solid-state carbon monoxide. We demonstrate H$_2$CO formation via the reaction of carbon atoms with amorphous solid water. Crucial to our proposed mechanism is a concerted proton transfer catalyzed by the water hydrogen bonding network. Consequently, the reactions $^3$C + H$_2$O -> $^3$HCOH and $^1$HCOH -> $^1$H$_2$CO can take place with low or without barriers, contrary to the high-barrier traditional internal hydrogen migration. These low barriers or absence thereof explain the very small kinetic isotope effect in our experiments when comparing the formation of H$_2$CO to D$_2$CO. Our results reconcile the disagreement found in the literature on the reaction route: C + H$_2$O -> H$_2$CO. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.15887v1-abstract-full').style.display = 'none'; document.getElementById('2110.15887v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in JPCL</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2110.15881">arXiv:2110.15881</a> <span> [<a href="https://arxiv.org/pdf/2110.15881">pdf</a>, <a href="https://arxiv.org/format/2110.15881">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac51d1">10.3847/1538-4357/ac51d1 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Methane formation in cold regions from carbon atoms and molecular hydrogen </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Lamberts%2C+T">Thanja Lamberts</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">Gleb Fedoseev</a>, <a href="/search/?searchtype=author&query=van+Hemert%2C+M">Marc van Hemert</a>, <a href="/search/?searchtype=author&query=Qasim%2C+D">Danna Qasim</a>, <a href="/search/?searchtype=author&query=Chuang%2C+K">Ko-Ju Chuang</a>, <a href="/search/?searchtype=author&query=Santos%2C+J+C">Julia C. Santos</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">Harold Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2110.15881v1-abstract-short" style="display: inline;"> Methane is typically thought to be formed in the solid state on the surface of cold interstellar icy grain mantles via the successive atomic hydrogenation of a carbon atom. In the current work we investigate the potential role of molecular hydrogen in the CH$_4$ reaction network. We make use of an ultra-high vacuum cryogenic setup combining an atomic carbon atom beam and both atomic and/or molecul… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.15881v1-abstract-full').style.display = 'inline'; document.getElementById('2110.15881v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.15881v1-abstract-full" style="display: none;"> Methane is typically thought to be formed in the solid state on the surface of cold interstellar icy grain mantles via the successive atomic hydrogenation of a carbon atom. In the current work we investigate the potential role of molecular hydrogen in the CH$_4$ reaction network. We make use of an ultra-high vacuum cryogenic setup combining an atomic carbon atom beam and both atomic and/or molecular beams of hydrogen and deuterium on a H$_2$O ice. These experiments lead to the formation of methane isotopologues detected in situ through reflection absorption infrared spectroscopy. Most notably, CH$_4$ is formed in an experiment combining C atoms with H$_2$ on amorphous solid water, albeit slower than in experiments with H atoms present. Furthermore, CH$_2$D$_2$ is detected in an experiment of C atoms with H$_2$ and D$_2$ on H$_2$O ice. CD$_4$, however, is only formed when D atoms are present in the experiment. These findings have been rationalized by means of computational chemical insights. This leads to the following conclusions: a) the reaction C + H$_2$ -> CH$_2$ can take place, although not barrierless in the presence of water, b) the reaction CH + H$_2$ -> CH$_3$ is barrierless, but has not yet been included in astrochemical models, c) the reactions CH$_2$ + H$_2$ -> CH$_3$ + H and CH$_3$ + H$_2$ -> CH$_4$ + H can take place only via a tunneling mechanism and d) molecular hydrogen possibly plays a more important role in the solid-state formation of methane than assumed so far. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.15881v1-abstract-full').style.display = 'none'; document.getElementById('2110.15881v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Submitted to ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2011.06145">arXiv:2011.06145</a> <span> [<a href="https://arxiv.org/pdf/2011.06145">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41550-020-01249-0">10.1038/s41550-020-01249-0 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A non-energetic mechanism for glycine formation in the interstellar medium </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S. Ioppolo</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">G. Fedoseev</a>, <a href="/search/?searchtype=author&query=Chuang%2C+K+-">K. -J. Chuang</a>, <a href="/search/?searchtype=author&query=Cuppen%2C+H+M">H. M. Cuppen</a>, <a href="/search/?searchtype=author&query=Clements%2C+A+R">A. R. Clements</a>, <a href="/search/?searchtype=author&query=Jin%2C+M">M. Jin</a>, <a href="/search/?searchtype=author&query=Garrod%2C+R+T">R. T. Garrod</a>, <a href="/search/?searchtype=author&query=Qasim%2C+D">D. Qasim</a>, <a href="/search/?searchtype=author&query=Kofman%2C+V">V. Kofman</a>, <a href="/search/?searchtype=author&query=van+Dishoeck%2C+E+F">E. F. van Dishoeck</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">H. Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2011.06145v2-abstract-short" style="display: inline;"> The detection of the amino acid glycine and its amine precursor methylamine on the comet 67P/Churyumov-Gerasimenko by the Rosetta mission provides strong evidence for a cosmic origin of prebiotics on Earth. How and when such complex organic molecules form along the process of star- and planet-formation remains debated. We report the first laboratory detection of glycine formed in the solid phase t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.06145v2-abstract-full').style.display = 'inline'; document.getElementById('2011.06145v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2011.06145v2-abstract-full" style="display: none;"> The detection of the amino acid glycine and its amine precursor methylamine on the comet 67P/Churyumov-Gerasimenko by the Rosetta mission provides strong evidence for a cosmic origin of prebiotics on Earth. How and when such complex organic molecules form along the process of star- and planet-formation remains debated. We report the first laboratory detection of glycine formed in the solid phase through atom and radical-radical addition surface reactions under cold dense interstellar cloud conditions. Our experiments, supported by astrochemical models, suggest that glycine forms without the need for energetic irradiation, such as UV photons and cosmic rays, in interstellar water-rich ices, where it remains preserved, in a much earlier star-formation stage than previously assumed. We also confirm that solid methylamine is an important side-reaction product. A prestellar formation of glycine on ice grains provides the basis for a complex and ubiquitous prebiotic chemistry in space enriching the chemical content of planet-forming material. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.06145v2-abstract-full').style.display = 'none'; document.getElementById('2011.06145v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Preprint of the original submitted version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Astronomy published online 16 November 2020 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2004.06681">arXiv:2004.06681</a> <span> [<a href="https://arxiv.org/pdf/2004.06681">pdf</a>, <a href="https://arxiv.org/format/2004.06681">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/5.0003692">10.1063/5.0003692 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A cryogenic ice setup to simulate carbon atom reactions in interstellar ices </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Qasim%2C+D">D. Qasim</a>, <a href="/search/?searchtype=author&query=Witlox%2C+M+J+A">M. J. A. Witlox</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">G. Fedoseev</a>, <a href="/search/?searchtype=author&query=Chuang%2C+K+-">K. -J. Chuang</a>, <a href="/search/?searchtype=author&query=Banu%2C+T">T. Banu</a>, <a href="/search/?searchtype=author&query=Krasnokutski%2C+S+A">S. A. Krasnokutski</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S. Ioppolo</a>, <a href="/search/?searchtype=author&query=Kastner%2C+J">J. Kastner</a>, <a href="/search/?searchtype=author&query=van+Dishoeck%2C+E+F">E. F. van Dishoeck</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">H. Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2004.06681v2-abstract-short" style="display: inline;"> The design, implementation, and performance of a customized carbon atom beam source for the purpose of investigating solid-state reaction routes in interstellar ices in molecular clouds are discussed. The source is integrated into an existing ultrahigh vacuum setup, SURFace REaction SImulation DEvice (SURFRESIDE$^{2}$), which extends this double atom (H/D, O, and N) beamline apparatus with a third… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.06681v2-abstract-full').style.display = 'inline'; document.getElementById('2004.06681v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2004.06681v2-abstract-full" style="display: none;"> The design, implementation, and performance of a customized carbon atom beam source for the purpose of investigating solid-state reaction routes in interstellar ices in molecular clouds are discussed. The source is integrated into an existing ultrahigh vacuum setup, SURFace REaction SImulation DEvice (SURFRESIDE$^{2}$), which extends this double atom (H/D, O, and N) beamline apparatus with a third atom (C) beamline to a unique system that is fully suited to explore complex organic molecule solid-state formation under representative interstellar cloud conditions. The parameter space for this system is discussed, which includes the flux of the carbon atoms hitting the ice sample, their temperature, and the potential impact of temperature on ice reactions. Much effort has been put into constraining the beam size to within the limits of the sample size with the aim to reduce carbon pollution inside the setup. How the C-atom beam performs is quantitatively studied through the example experiment, C + $^{18}$O$_2$, and supported by computationally-derived activation barriers. The potential for this source to study the solid-state formation of interstellar complex organic molecules through C-atom reactions is discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.06681v2-abstract-full').style.display = 'none'; document.getElementById('2004.06681v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in Review of Scientific Instruments</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Review of Scientific Instruments 2020 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2004.02506">arXiv:2004.02506</a> <span> [<a href="https://arxiv.org/pdf/2004.02506">pdf</a>, <a href="https://arxiv.org/format/2004.02506">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41550-020-1054-y">10.1038/s41550-020-1054-y <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> An experimental study of the surface formation of methane in interstellar molecular clouds </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Qasim%2C+D">D. Qasim</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">G. Fedoseev</a>, <a href="/search/?searchtype=author&query=Chuang%2C+K+-">K. -J. Chuang</a>, <a href="/search/?searchtype=author&query=He%2C+J">J. He</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S. Ioppolo</a>, <a href="/search/?searchtype=author&query=van+Dishoeck%2C+E+F">E. F. van Dishoeck</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">H. Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2004.02506v2-abstract-short" style="display: inline;"> Methane is one of the simplest stable molecules that is both abundant and widely distributed across space. It is thought to have partial origin from interstellar molecular clouds, which are near the beginning of the star formation cycle. Observational surveys of CH$_4$ ice towards low- and high-mass young stellar objects showed that much of the CH$_4$ is expected to be formed by the hydrogenation… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.02506v2-abstract-full').style.display = 'inline'; document.getElementById('2004.02506v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2004.02506v2-abstract-full" style="display: none;"> Methane is one of the simplest stable molecules that is both abundant and widely distributed across space. It is thought to have partial origin from interstellar molecular clouds, which are near the beginning of the star formation cycle. Observational surveys of CH$_4$ ice towards low- and high-mass young stellar objects showed that much of the CH$_4$ is expected to be formed by the hydrogenation of C on dust grains, and that CH$_4$ ice is strongly correlated with solid H$_2$O. Yet, this has not been investigated under controlled laboratory conditions, as carbon-atom chemistry of interstellar ice analogues has not been experimentally realized. In this study, we successfully demonstrate with a C-atom beam implemented in an ultrahigh vacuum apparatus the formation of CH$_4$ ice in two separate co-deposition experiments: C + H on a 10 K surface to mimic CH$_4$ formation right before H$_2$O ice is formed on the dust grain, and C + H + H$_2$O on a 10 K surface to mimic CH$_4$ formed simultaneously with H$_2$O ice. We confirm that CH$_4$ can be formed by the reaction of atomic C and H, and that the CH$_4$ formation rate is 2 times greater when CH$_4$ is formed within a H$_2$O-rich ice. This is in agreement with the observational finding that interstellar CH$_4$ and H$_2$O form together in the polar ice phase, i.e., when C- and H-atoms simultaneously accrete with O-atoms on dust grains. For the first time, the conditions that lead to interstellar CH$_4$ (and CD$_4$) ice formation are reported, and can be incorporated into astrochemical models to further constrain CH$_4$ chemistry in the interstellar medium and in other regions where CH$_4$ is inherited. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.02506v2-abstract-full').style.display = 'none'; document.getElementById('2004.02506v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Astronomy April 2020 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2002.06971">arXiv:2002.06971</a> <span> [<a href="https://arxiv.org/pdf/2002.06971">pdf</a>, <a href="https://arxiv.org/format/2002.06971">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201937302">10.1051/0004-6361/201937302 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Formation of complex molecules in translucent clouds: Acetaldehyde, vinyl alcohol, ketene, and ethanol via nonenergetic processing of C2H2 ice </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Chuang%2C+K+-">K. -J. Chuang</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">G. Fedoseev</a>, <a href="/search/?searchtype=author&query=Qasim%2C+D">D. Qasim</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S. Ioppolo</a>, <a href="/search/?searchtype=author&query=J%C3%A4ger%2C+C">C. J盲ger</a>, <a href="/search/?searchtype=author&query=Henning%2C+T">Th. Henning</a>, <a href="/search/?searchtype=author&query=Palumbo%2C+M+E">M. E. Palumbo</a>, <a href="/search/?searchtype=author&query=van+Dishoeck%2C+E+F">E. F. van Dishoeck</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">H. Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2002.06971v1-abstract-short" style="display: inline;"> Complex organic molecules (COMs) have been identified toward high- and low-mass protostars as well as molecular clouds, suggesting that these interstellar species originate from the early stage(s) of starformation. The reaction pathways resulting in COMs described by the formula C$_2$H$_\text{n}$O are still under debate. In this work, we investigate the laboratory possible solid-state reactions th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.06971v1-abstract-full').style.display = 'inline'; document.getElementById('2002.06971v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2002.06971v1-abstract-full" style="display: none;"> Complex organic molecules (COMs) have been identified toward high- and low-mass protostars as well as molecular clouds, suggesting that these interstellar species originate from the early stage(s) of starformation. The reaction pathways resulting in COMs described by the formula C$_2$H$_\text{n}$O are still under debate. In this work, we investigate the laboratory possible solid-state reactions that involve simple hydrocarbons and OH-radicals along with H$_2$O ice under translucent cloud conditions (1$\leq$A$_V$$\leq$5 and \textit{n}$_\text{H}$$\sim$10$^3$ cm$^{-3}$). We focus on the interactions of C$_2$H$_2$ with H-atoms and OH-radicals, which are produced along the H$_2$O formation sequence on grain surfaces at 10 K. Ultra-high vacuum (UHV) experiments were performed to study the surface chemistry observed during C$_2$H$_2$ + O$_2$ + H codeposition, where O$_2$ was used for the in-situ generation of OH-radicals. Reflection absorption infrared spectroscopy (RAIRS) was applied to in situ monitor the initial and newly formed species. After that, a temperature-programmed desorption experiment combined with a Quadrupole mass spectrometer (TPD-QMS) was used as a complementary analytical tool. The investigated 10 K surface chemistry of C$_2$H$_2$ with H-atoms and OH-radicals not only results in semi and fully saturated hydrocarbons, such as ethylene (C$_2$H$_4$) and ethane (C$_2$H$_6$), but it also leads to the formation of COMs, such as vinyl alcohol, acetaldehyde, ketene, ethanol, and possibly acetic acid. It is concluded that OH-radical addition reactions to C$_2$H$_2$, acting as a molecular backbone, followed by isomerization (i.e., keto-enol tautomerization) via an intermolecular pathway and successive hydrogenation provides a so far experimentally unreported solid-state route for the formation of these species without the need of energetic input. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.06971v1-abstract-full').style.display = 'none'; document.getElementById('2002.06971v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 February, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 12 figures, 2 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 635, A199 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1906.06508">arXiv:1906.06508</a> <span> [<a href="https://arxiv.org/pdf/1906.06508">pdf</a>, <a href="https://arxiv.org/format/1906.06508">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1017/S174392131900975X">10.1017/S174392131900975X <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Synthesis of solid-state Complex Organic Molecules through accretion of simple species at low temperatures </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Qasim%2C+D">D. Qasim</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">G. Fedoseev</a>, <a href="/search/?searchtype=author&query=Chuang%2C+K+-">K. -J. Chuang</a>, <a href="/search/?searchtype=author&query=Taquet%2C+V">V. Taquet</a>, <a href="/search/?searchtype=author&query=Lamberts%2C+T">T. Lamberts</a>, <a href="/search/?searchtype=author&query=He%2C+J">J. He</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S. Ioppolo</a>, <a href="/search/?searchtype=author&query=van+Dishoeck%2C+E+F">E. F. van Dishoeck</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">H. Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1906.06508v1-abstract-short" style="display: inline;"> Complex organic molecules (COMs) have been detected in the gas-phase in cold and lightless molecular cores. Recent solid-state laboratory experiments have provided strong evidence that COMs can be formed on icy grains through 'non-energetic' processes. In this contribution, we show that propanal and 1-propanol can be formed in this way at the low temperature of 10 K. Propanal has already been dete… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.06508v1-abstract-full').style.display = 'inline'; document.getElementById('1906.06508v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1906.06508v1-abstract-full" style="display: none;"> Complex organic molecules (COMs) have been detected in the gas-phase in cold and lightless molecular cores. Recent solid-state laboratory experiments have provided strong evidence that COMs can be formed on icy grains through 'non-energetic' processes. In this contribution, we show that propanal and 1-propanol can be formed in this way at the low temperature of 10 K. Propanal has already been detected in space. 1-propanol is an astrobiologically relevant molecule, as it is a primary alcohol, and has not been astronomically detected. Propanal is the major product formed in the C2H2 + CO + H experiment, and 1-propanol is detected in the subsequent propanal + H experiment. The results are published in Qasim et al. (2019c). ALMA observations towards IRAS 16293-2422B are discussed and provide a 1-propanol:propanal upper limit of < 0.35 - 0.55, which are complemented by computationally-derived activation barriers in addition to the performed laboratory experiments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.06508v1-abstract-full').style.display = 'none'; document.getElementById('1906.06508v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Proceedings IAU Symposium No. 350, 2019, Laboratory Astrophysics: from Observations to Interpretation</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1905.07801">arXiv:1905.07801</a> <span> [<a href="https://arxiv.org/pdf/1905.07801">pdf</a>, <a href="https://arxiv.org/format/1905.07801">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201935217">10.1051/0004-6361/201935217 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Formation of interstellar propanal and 1-propanol ice: a pathway involving solid-state CO hydrogenation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Qasim%2C+D">D. Qasim</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">G. Fedoseev</a>, <a href="/search/?searchtype=author&query=Chuang%2C+K+-">K. -J. Chuang</a>, <a href="/search/?searchtype=author&query=Taquet%2C+V">V. Taquet</a>, <a href="/search/?searchtype=author&query=Lamberts%2C+T">T. Lamberts</a>, <a href="/search/?searchtype=author&query=He%2C+J">J. He</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S. Ioppolo</a>, <a href="/search/?searchtype=author&query=van+Dishoeck%2C+E+F">E. F. van Dishoeck</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">H. Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1905.07801v3-abstract-short" style="display: inline;"> 1-propanol (CH3CH2CH2OH) is a three carbon-bearing representative of primary linear alcohols that may have its origin in the cold dark cores in interstellar space. To test this, we investigated in the laboratory whether 1-propanol ice can be formed along pathways possibly relevant to the prestellar core phase. We aim to show in a two-step approach that 1-propanol can be formed through reaction ste… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.07801v3-abstract-full').style.display = 'inline'; document.getElementById('1905.07801v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1905.07801v3-abstract-full" style="display: none;"> 1-propanol (CH3CH2CH2OH) is a three carbon-bearing representative of primary linear alcohols that may have its origin in the cold dark cores in interstellar space. To test this, we investigated in the laboratory whether 1-propanol ice can be formed along pathways possibly relevant to the prestellar core phase. We aim to show in a two-step approach that 1-propanol can be formed through reaction steps that are expected to take place during the heavy CO freeze-out stage by adding C2H2 into the CO + H hydrogenation network via the formation of propanal (CH3CH2CHO) as an intermediate and its subsequent hydrogenation. Temperature programmed desorption-quadrupole mass spectrometry (TPD-QMS) is used to identify the newly formed propanal and 1-propanol. Reflection absorption infrared spectroscopy (RAIRS) is used as a complementary diagnostic tool. The mechanisms that can contribute to the formation of solid-state propanal and 1-propanol, as well as other organic compounds, during the heavy CO freeze-out stage are constrained by both laboratory experiments and theoretical calculations. Here it is shown that recombination of HCO radicals, formed upon CO hydrogenation, with radicals formed upon C2H2 processing - H2CCH and H3CCH2 - offers possible reaction pathways to solid-state propanal and 1-propanol formation. This extends the already important role of the CO hydrogenation chain in the formation of larger COMs (complex organic molecules). The results are used to compare with ALMA observations. The resulting 1-propanol:propanal ratio concludes an upper limit of < 0:35-0:55, which is complemented by computationally-derived activation barriers in addition to the experimental results. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.07801v3-abstract-full').style.display = 'none'; document.getElementById('1905.07801v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in Astronomy and Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 627, A1 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1905.06767">arXiv:1905.06767</a> <span> [<a href="https://arxiv.org/pdf/1905.06767">pdf</a>, <a href="https://arxiv.org/format/1905.06767">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201935068">10.1051/0004-6361/201935068 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Extension of the HCOOH and CO2 solid-state reaction network during the CO freeze-out stage: inclusion of H2CO </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Qasim%2C+D">D. Qasim</a>, <a href="/search/?searchtype=author&query=Lamberts%2C+T">T. Lamberts</a>, <a href="/search/?searchtype=author&query=He%2C+J">J. He</a>, <a href="/search/?searchtype=author&query=Chuang%2C+K+-">K. -J. Chuang</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">G. Fedoseev</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S. Ioppolo</a>, <a href="/search/?searchtype=author&query=Boogert%2C+A+C+A">A. C. A. Boogert</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">H. Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1905.06767v3-abstract-short" style="display: inline;"> Formic acid (HCOOH) and carbon dioxide (CO2) are simple species that have been detected in the interstellar medium. The solid-state formation pathways of these species under experimental conditions relevant to prestellar cores are primarily based off of weak infrared transitions of the HOCO complex and usually pertain to the H2O-rich ice phase, and therefore more experimental data are desired. In… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.06767v3-abstract-full').style.display = 'inline'; document.getElementById('1905.06767v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1905.06767v3-abstract-full" style="display: none;"> Formic acid (HCOOH) and carbon dioxide (CO2) are simple species that have been detected in the interstellar medium. The solid-state formation pathways of these species under experimental conditions relevant to prestellar cores are primarily based off of weak infrared transitions of the HOCO complex and usually pertain to the H2O-rich ice phase, and therefore more experimental data are desired. In this article, we present a new and additional solid-state reaction pathway that can form HCOOH and CO2 ice at 10 K 'non-energetically' in the laboratory under conditions related to the "heavy" CO freeze-out stage in dense interstellar clouds, i.e., by the hydrogenation of an H2CO:O2 ice mixture. This pathway is used to piece together the HCOOH and CO2 formation routes when H2CO or CO reacts with H and OH radicals. Temperature programmed desorption - quadrupole mass spectrometry (TPD-QMS) is used to confirm the formation and pathways of newly synthesized ice species as well as to provide information on relative molecular abundances. Reflection absorption infrared spectroscopy (RAIRS) is additionally employed to characterize reaction products and determine relative molecular abundances. We find that for the conditions investigated in conjunction with theoretical results from the literature, H+HOCO and HCO+OH lead to the formation of HCOOH ice in our experiments. Which reaction is more dominant can be determined if the H+HOCO branching ratio is more constrained by computational simulations, as the HCOOH:CO2 abundance ratio is experimentally measured to be around 1.8:1. H+HOCO is more likely than OH+CO (without HOCO formation) to form CO2. Isotope experiments presented here further validate that H+HOCO is the dominant route for HCOOH ice formation in a CO-rich CO:O2 ice mixture that is hydrogenated. These data will help in the search and positive identification of HCOOH ice in prestellar cores. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.06767v3-abstract-full').style.display = 'none'; document.getElementById('1905.06767v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in Astronomy and Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 626, A118 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1905.05063">arXiv:1905.05063</a> <span> [<a href="https://arxiv.org/pdf/1905.05063">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acsearthspacechem.9b00062">10.1021/acsearthspacechem.9b00062 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Alcohols on the rocks: solid-state formation in a H3CCCH + OH cocktail under dark cloud conditions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Qasim%2C+D">D. Qasim</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">G. Fedoseev</a>, <a href="/search/?searchtype=author&query=Lamberts%2C+T">T. Lamberts</a>, <a href="/search/?searchtype=author&query=Chuang%2C+K+-">K. -J. Chuang</a>, <a href="/search/?searchtype=author&query=He%2C+J">J. He</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S. Ioppolo</a>, <a href="/search/?searchtype=author&query=K%C3%A4stner%2C+J">J. K盲stner</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">H. Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1905.05063v1-abstract-short" style="display: inline;"> A number of recent experimental studies have shown that solid-state complex organic molecules (COMs) can form under conditions that are relevant to the CO freeze-out stage in dense clouds. In this work, we show that alcohols can be formed well before the CO freeze-out stage (i.e., in the H2O-rich ice phase). This joint experimental and computational investigation shows that the isomers, n- and i-p… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.05063v1-abstract-full').style.display = 'inline'; document.getElementById('1905.05063v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1905.05063v1-abstract-full" style="display: none;"> A number of recent experimental studies have shown that solid-state complex organic molecules (COMs) can form under conditions that are relevant to the CO freeze-out stage in dense clouds. In this work, we show that alcohols can be formed well before the CO freeze-out stage (i.e., in the H2O-rich ice phase). This joint experimental and computational investigation shows that the isomers, n- and i-propanol (H3CCH2CH2OH and H3CCHOHCH3) and n- and i-propenol (H3CCHCHOH and H3CCOHCH2), can be formed in radical-addition reactions starting from propyne (H3CCCH) + OH at the low temperature of 10 K, where H3CCCH is one of the simplest representatives of stable carbon chains already identified in the interstellar medium (ISM). The resulting average abundance ratio of 1:1 for n-propanol:i-propanol is aligned with the conclusions from the computational work that the geometric orientation of strongly interacting species is influential to the extent of which 'mechanism' is participating, and that an assortment of geometries leads to an averaged-out effect. Three isomers of propanediol are also tentatively identified in the experiments. It is also shown that propene and propane (H3CCHCH2 and H3CCH2CH3) are formed from the hydrogenation of H3CCCH. Computationally-derived activation barriers give additional insight into what types of reactions and mechanisms are more likely to occur in the laboratory and in the ISM. Our findings not only suggest that the alcohols studied here share common chemical pathways and therefore can show up simultaneously in astronomical surveys, but also that their extended counterparts that derive from polyynes containing H3C(CC)nH structures may exist in the ISM. Such larger species, like fatty alcohols, are the possible constituents of simple lipids that primitive cell membranes on the early Earth are thought to be partially composed of. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.05063v1-abstract-full').style.display = 'none'; document.getElementById('1905.05063v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Published in ACS Earth and Space Chemistry, Complex Organic Molecules (COMs) in Star-Forming Regions special issue</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1809.10507">arXiv:1809.10507</a> <span> [<a href="https://arxiv.org/pdf/1809.10507">pdf</a>, <a href="https://arxiv.org/format/1809.10507">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201833439">10.1051/0004-6361/201833439 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> H2 chemistry in interstellar ices: the case of CO ice hydrogenation in UV irradiated CO:H2 ice mixtures </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Chuang%2C+K+-">K. -J. Chuang</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">G. Fedoseev</a>, <a href="/search/?searchtype=author&query=Qasim%2C+D">D. Qasim</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S. Ioppolo</a>, <a href="/search/?searchtype=author&query=van+Dishoeck%2C+E+F">E. F. van Dishoeck</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">H. Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1809.10507v1-abstract-short" style="display: inline;"> Context. In dense clouds, hydrogenation reactions on icy dust grains are key in the formation of molecules, like formaldehyde, methanol, and complex organic molecules (COMs). These species form through the sequential hydrogenation of CO ice. Although molecular hydrogen (H2) abundances can be four orders of magnitude higher than those of free H-atoms in dense clouds, H2 surface chemistry has been l… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.10507v1-abstract-full').style.display = 'inline'; document.getElementById('1809.10507v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1809.10507v1-abstract-full" style="display: none;"> Context. In dense clouds, hydrogenation reactions on icy dust grains are key in the formation of molecules, like formaldehyde, methanol, and complex organic molecules (COMs). These species form through the sequential hydrogenation of CO ice. Although molecular hydrogen (H2) abundances can be four orders of magnitude higher than those of free H-atoms in dense clouds, H2 surface chemistry has been largely ignored; several laboratory studies show that H2 does not actively participate in non-energetic ice chemistry because of the high activation energies required. Aims. For the example of CO ice hydrogenation, we experimentally investigated the potential role of H2 molecules on the surface chemistry when energetic processing (i.e., UV photolysis) is involved. We test whether additional hydrogenation pathways become available upon UV irradiation of a CO:H2 ice mixture and whether this reaction mechanism also applies to other chemical systems. Methods. Ultra-high vacuum (UHV) experiments were performed at 8~20 K. A pre-deposited solid mixture of CO:H2 was irradiated with UV-photons. Reflection absorption infrared spectroscopy (RAIRS) was used as an in situ diagnostic tool. Single reaction steps and possible isotopic effects were studied by comparing results from CO:H2 and CO:D2 ice mixtures. Results. After UV-irradiation of a CO:H2 ice mixture, two photon-induced products, HCO and H2CO, are unambiguously detected. The proposed reaction mechanism involves electronically excited CO in the following reaction steps: CO + h谓->CO*, CO* + H2->HCO + H where newly formed H-atoms are then available for further hydrogenation reactions. The HCO formation yields have a strong temperature dependence for the investigated regime, which is most likely linked to the H2 sticking coefficient. Finally, the astronomical relevance of this photo-induced reaction channel is discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.10507v1-abstract-full').style.display = 'none'; document.getElementById('1809.10507v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 September, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 6 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 617, A87 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1806.06215">arXiv:1806.06215</a> <span> [<a href="https://arxiv.org/pdf/1806.06215">pdf</a>, <a href="https://arxiv.org/format/1806.06215">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/aaa24e">10.3847/1538-4357/aaa24e <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Reactive Desorption of CO Hydrogenation Products under Cold Pre-stellar Core Conditions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Chuang%2C+K">K-J Chuang</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">G Fedoseev</a>, <a href="/search/?searchtype=author&query=Qasim%2C+D">D Qasim</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S Ioppolo</a>, <a href="/search/?searchtype=author&query=van+Dishoeck%2C+E">EF van Dishoeck</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">H Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1806.06215v1-abstract-short" style="display: inline;"> The astronomical gas-phase detection of simple species and small organic molecules in cold pre-stellar cores, with abundances as high as $\sim$$10^{-8}-10^{-9}$ n$_\text{H}$, contradicts the generally accepted idea that at $10$ K, such species should be fully frozen out on grain surfaces. A physical or chemical mechanism that results in a net transfer from solid-state species into the gas phase of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.06215v1-abstract-full').style.display = 'inline'; document.getElementById('1806.06215v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1806.06215v1-abstract-full" style="display: none;"> The astronomical gas-phase detection of simple species and small organic molecules in cold pre-stellar cores, with abundances as high as $\sim$$10^{-8}-10^{-9}$ n$_\text{H}$, contradicts the generally accepted idea that at $10$ K, such species should be fully frozen out on grain surfaces. A physical or chemical mechanism that results in a net transfer from solid-state species into the gas phase offers a possible explanation. Reactive desorption, i.e., desorption following the exothermic formation of a species, is one of the options that has been proposed. In astronomical models, the fraction of molecules desorbed through this process is handled as a free parameter, as experimental studies quantifying the impact of exothermicity on desorption efficiencies are largely lacking. In this work, we present a detailed laboratory study with the goal of deriving an upper limit for the reactive desorption efficiency of species involved in the CO-H$_2$CO-CH$_3$OH solid-state hydrogenation reaction chain. The limit for the overall reactive desorption fraction is derived by precisely investigating the solid-state elemental carbon budget, using reflection absorption infrared spectroscopy and the calibrated solid-state band-strength values for CO, H$_2$CO and CH$_3$OH. We find that for temperatures in the range of $10$ to $14$ K, an upper limit of $0.24\pm 0.02$ for the overall elemental carbon loss upon CO conversion into CH$_3$OH. This corresponds with an effective reaction desorption fraction of $\leq$$0.07$ per hydrogenation step, or $\leq$$0.02$ per H-atom induced reaction, assuming that H-atom addition and abstraction reactions equally contribute to the overall reactive desorption fraction along the hydrogenation sequence. The astronomical relevance of this finding is discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.06215v1-abstract-full').style.display = 'none'; document.getElementById('1806.06215v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 June, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 7 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1801.10154">arXiv:1801.10154</a> <span> [<a href="https://arxiv.org/pdf/1801.10154">pdf</a>, <a href="https://arxiv.org/format/1801.10154">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201732355">10.1051/0004-6361/201732355 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Formation of interstellar methanol ice prior to the heavy CO freeze-out stage </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Qasim%2C+D">D. Qasim</a>, <a href="/search/?searchtype=author&query=Chuang%2C+K+-">K. -J. Chuang</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">G. Fedoseev</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S. Ioppolo</a>, <a href="/search/?searchtype=author&query=Boogert%2C+A+C+A">A. C. A. Boogert</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">H. Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1801.10154v1-abstract-short" style="display: inline;"> The formation of methanol (CH3OH) on icy grain mantles during the star formation cycle is mainly associated with the CO freeze-out stage. Yet there are reasons to believe that CH3OH also can form at an earlier period of interstellar ice evolution in CO-poor and H2O-rich ices. This work focuses on CH3OH formation in a H2O-rich interstellar ice environment following the OH-mediated H-abstraction in… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.10154v1-abstract-full').style.display = 'inline'; document.getElementById('1801.10154v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1801.10154v1-abstract-full" style="display: none;"> The formation of methanol (CH3OH) on icy grain mantles during the star formation cycle is mainly associated with the CO freeze-out stage. Yet there are reasons to believe that CH3OH also can form at an earlier period of interstellar ice evolution in CO-poor and H2O-rich ices. This work focuses on CH3OH formation in a H2O-rich interstellar ice environment following the OH-mediated H-abstraction in the reaction, CH4 + OH. Experimental conditions are systematically varied to constrain the CH3OH formation yield at astronomically relevant temperatures. CH4, O2, and hydrogen atoms are co-deposited in an ultrahigh vacuum chamber at 10-20 K. OH radicals are generated by the H + O2 surface reaction. Temperature programmed desorption - quadrupole mass spectrometry (TPD-QMS) is used to characterize CH3OH formation, and is complemented with reflection absorption infrared spectroscopy (RAIRS) for CH3OH characterization and quantitation. CH3OH formation is shown to be possible by the sequential surface reaction chain, CH4 + OH -> CH3 + H2O and CH3 + OH -> CH3OH at 10-20 K. This reaction is enhanced by tunneling, as noted in a recent theoretical investigation (Lamberts et al. 2017). The CH3OH formation yield via the CH4 + OH route versus the CO + H route is approximately 20 times smaller for the laboratory settings studied. The astronomical relevance of the new formation channel investigated here is discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.10154v1-abstract-full').style.display = 'none'; document.getElementById('1801.10154v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 January, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in Astronomy and Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 612, A83 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1705.09625">arXiv:1705.09625</a> <span> [<a href="https://arxiv.org/pdf/1705.09625">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/aa74dc">10.3847/1538-4357/aa74dc <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Formation of Glycerol through Hydrogenation of CO ice under Prestellar Core Conditions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Fedoseev%2C+G">Gleb Fedoseev</a>, <a href="/search/?searchtype=author&query=Chuang%2C+K">Ko-Ju Chuang</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">Sergio Ioppolo</a>, <a href="/search/?searchtype=author&query=Qasim%2C+D">Danna Qasim</a>, <a href="/search/?searchtype=author&query=van+Dishoeck%2C+E+F">Ewine F. van Dishoeck</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">Harold Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1705.09625v1-abstract-short" style="display: inline;"> Observational studies reveal that complex organic molecules (COMs) can be found in various objects associated with different star formation stages. The identification of COMs in prestellar cores, i.e., cold environments in which thermally induced chemistry can be excluded and radiolysis is limited by cosmic rays and cosmic ray induced UV-photons, is particularly important as this stage sets up the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.09625v1-abstract-full').style.display = 'inline'; document.getElementById('1705.09625v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1705.09625v1-abstract-full" style="display: none;"> Observational studies reveal that complex organic molecules (COMs) can be found in various objects associated with different star formation stages. The identification of COMs in prestellar cores, i.e., cold environments in which thermally induced chemistry can be excluded and radiolysis is limited by cosmic rays and cosmic ray induced UV-photons, is particularly important as this stage sets up the initial chemical composition from which ultimately stars and planets evolve. Recent laboratory results demonstrate that molecules as complex as glycolaldehyde and ethylene glycol are efficiently formed on icy dust grains via non-energetic atom addition reactions between accreting H atoms and CO molecules, a process that dominates surface chemistry during the 'CO-freeze out stage' in dense cores. In the present study we demonstrate that a similar mechanism results in the formation of the biologically relevant molecule glycerol - HOCH2CH(OH)CH2OH - a three-carbon bearing sugar alcohol necessary for the formation of membranes of modern living cells and organelles. Our experimental results are fully consistent with a suggested reaction scheme in which glycerol is formed along a chain of radical-radical and radical-molecule interactions between various reactive intermediates produced upon hydrogenation of CO ice or its hydrogenation products. The tentative identification of the chemically related simple sugar glyceraldehyde - HOCH2CH(OH)CHO - is discussed as well. These new laboratory findings indicate that the proposed reaction mechanism holds much potential to form even more complex sugar alcohols and simple sugars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.09625v1-abstract-full').style.display = 'none'; document.getElementById('1705.09625v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 May, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1705.07680">arXiv:1705.07680</a> <span> [<a href="https://arxiv.org/pdf/1705.07680">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stx222">10.1093/mnras/stx222 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Production of complex organic molecules: H-atom addition versus UV irradiation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/?searchtype=author&query=Chuang%2C+K+-">K. -J. Chuang</a>, <a href="/search/?searchtype=author&query=Fedoseev%2C+G">G. Fedoseev</a>, <a href="/search/?searchtype=author&query=Qasim%2C+D">D. Qasim</a>, <a href="/search/?searchtype=author&query=Ioppolo%2C+S">S. Ioppolo</a>, <a href="/search/?searchtype=author&query=van+Dishoeck%2C+E+F">E. F. van Dishoeck</a>, <a href="/search/?searchtype=author&query=Linnartz%2C+H">H. Linnartz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1705.07680v1-abstract-short" style="display: inline;"> Complex organic molecules (COMs) have been identified in different environments in star- forming regions. Laboratory studies show that COMs form in the solid state, on icy grains, typically following a non-energetic (atom-addition) or energetic (UV-photon absorption) trigger. So far, such studies have been largely performed for single processes. Here, we present the first work that quantitatively… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.07680v1-abstract-full').style.display = 'inline'; document.getElementById('1705.07680v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1705.07680v1-abstract-full" style="display: none;"> Complex organic molecules (COMs) have been identified in different environments in star- forming regions. Laboratory studies show that COMs form in the solid state, on icy grains, typically following a non-energetic (atom-addition) or energetic (UV-photon absorption) trigger. So far, such studies have been largely performed for single processes. Here, we present the first work that quantitatively investigates both the relative importance and the cumulative effect of (non-)energetic processing. We focus on astronomically relevant CO:CH3OH = 4:1 ice analogues exposed to doses relevant for the collapse stage of dense clouds. Hydrogenation experiments result in the formation of methyl formate (MF HC(O)OCH3), glycolaldehyde (GA HC(O)CH2OH) and ethylene glycol (EG H2C(OH)CH2OH) at 14 K. The absolute abundances and the abundance fractions are found to be dependent on the H-atom/CO-CH3OH molecule ratios and on the overall deposition rate. In the case that ices are exposed to UV photons only, several different COMs are found. Typically, the abundance fractions are 0.2 for MF, 0.3 for GA and 0.5 for EG as opposed to the values found in pure hydrogenation experiments without UV in which MF is largely absent: 0.0, 0.2-0.6 and 0.8-0.4, respectively. In experiments where both are applied, overall COM abundances drop to about half of those found in the pure UV irradiation experiments, but the composition fractions are very similar. This implies COM ratios can be used as a diagnostic tool to derive the processing history of an ice. Solid-state branching ratios derived here for GA and EG compare well with observations, while the MF case cannot be explained by solid-state conditions investigated here. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.07680v1-abstract-full').style.display = 'none'; document.getElementById('1705.07680v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 May, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 8 figures, 1 table</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Mon Not R Astron Soc (2017) 467 (3): 2552-2565 </p> </li> </ol> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/about">About</a></li> <li><a href="https://info.arxiv.org/help">Help</a></li> </ul> </div> <div class="column"> <ul class="nav-spaced"> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>contact arXiv</title><desc>Click here to contact arXiv</desc><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg> <a href="https://info.arxiv.org/help/contact.html"> Contact</a> </li> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>subscribe to arXiv mailings</title><desc>Click here to subscribe</desc><path d="M476 3.2L12.5 270.6c-18.1 10.4-15.8 35.6 2.2 43.2L121 358.4l287.3-253.2c5.5-4.9 13.3 2.6 8.6 8.3L176 407v80.5c0 23.6 28.5 32.9 42.5 15.8L282 426l124.6 52.2c14.2 6 30.4-2.9 33-18.2l72-432C515 7.8 493.3-6.8 476 3.2z"/></svg> <a href="https://info.arxiv.org/help/subscribe"> Subscribe</a> </li> </ul> </div> </div> </div>   <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/license/index.html">Copyright</a></li> <li><a href="https://info.arxiv.org/help/policies/privacy_policy.html">Privacy Policy</a></li> </ul> </div> <div class="column sorry-app-links"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/web_accessibility.html">Web Accessibility Assistance</a></li> <li> <p class="help"> <a class="a11y-main-link" href="https://status.arxiv.org" target="_blank">arXiv Operational Status <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 512" class="icon filter-dark_grey" role="presentation"><path d="M224.3 273l-136 136c-9.4 9.4-24.6 9.4-33.9 0l-22.6-22.6c-9.4-9.4-9.4-24.6 0-33.9l96.4-96.4-96.4-96.4c-9.4-9.4-9.4-24.6 0-33.9L54.3 103c9.4-9.4 24.6-9.4 33.9 0l136 136c9.5 9.4 9.5 24.6.1 34z"/></svg></a><br> Get status notifications via <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/email/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg>email</a> or <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/slack/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512" class="icon filter-black" role="presentation"><path d="M94.12 315.1c0 25.9-21.16 47.06-47.06 47.06S0 341 0 315.1c0-25.9 21.16-47.06 47.06-47.06h47.06v47.06zm23.72 0c0-25.9 21.16-47.06 47.06-47.06s47.06 21.16 47.06 47.06v117.84c0 25.9-21.16 47.06-47.06 47.06s-47.06-21.16-47.06-47.06V315.1zm47.06-188.98c-25.9 0-47.06-21.16-47.06-47.06S139 32 164.9 32s47.06 21.16 47.06 47.06v47.06H164.9zm0 23.72c25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06H47.06C21.16 243.96 0 222.8 0 196.9s21.16-47.06 47.06-47.06H164.9zm188.98 47.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06h-47.06V196.9zm-23.72 0c0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06V79.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06V196.9zM283.1 385.88c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06v-47.06h47.06zm0-23.72c-25.9 0-47.06-21.16-47.06-47.06 0-25.9 21.16-47.06 47.06-47.06h117.84c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06H283.1z"/></svg>slack</a> </p> </li> </ul> </div> </div> </div>  </div> </footer> <script src="https://static.arxiv.org/static/base/1.0.0a5/js/member_acknowledgement.js"></script> </body> </html>

CINXE.COM

Search | arXiv e-print repository