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dc.contributor.authorPlacco, Vinicius M.
dc.contributor.authorBeers, Timothy C.
dc.contributor.authorStancliffe, Richard J.
dc.contributor.authorFrebel, Anna L.
dc.date.accessioned2015-01-22T16:47:21Z
dc.date.available2015-01-22T16:47:21Z
dc.date.issued2014-11
dc.date.submitted2014-09
dc.identifier.issn0004-637X
dc.identifier.issn1538-4357
dc.identifier.urihttp://hdl.handle.net/1721.1/93128
dc.description.abstractWe revisit the observed frequencies of carbon-enhanced metal-poor (CEMP) stars as a function of the metallicity in the Galaxy, using data from the literature with available high-resolution spectroscopy. Our analysis excludes stars exhibiting clear overabundances of neutron-capture elements and takes into account the expected depletion of surface carbon abundance that occurs due to CN processing on the upper red giant branch. This allows for the recovery of the initial carbon abundance of these stars, and thus for an accurate assessment of the frequencies of carbon-enhanced stars. The correction procedure we develop is based on stellar-evolution models and depends on the surface gravity, log g, of a given star. Our analysis indicates that for stars with [Fe/H] ≤–2.0, 20% exhibit [C/Fe] ≥+0.7. This fraction increases to 43% for [Fe/H] ≤–3.0 and 81% for [Fe/H] ≤–4.0, which is higher than have been previously inferred without taking the carbon abundance correction into account. These CEMP star frequencies provide important inputs for Galactic and stellar chemical evolution models, as they constrain the evolution of carbon at early times and the possible formation channels for the CEMP-no stars. We also have developed a public online tool with which carbon corrections using our procedure can be easily obtained.en_US
dc.description.sponsorshipNational Science Foundation (U.S.) (CAREER Grant AST-1255160)en_US
dc.language.isoen_US
dc.publisherIOP Publishingen_US
dc.relation.isversionofhttp://dx.doi.org/10.1088/0004-637X/797/1/21en_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.sourceAmerican Astronomical Societyen_US
dc.titleCARBON-ENHANCED METAL-POOR STAR FREQUENCIES IN THE GALAXY: CORRECTIONS FOR THE EFFECT OF EVOLUTIONARY STATUS ON CARBON ABUNDANCESen_US
dc.typeArticleen_US
dc.identifier.citationPlacco, Vinicius M., Anna Frebel, Timothy C. Beers, and Richard J. Stancliffe. “CARBON-ENHANCED METAL-POOR STAR FREQUENCIES IN THE GALAXY: CORRECTIONS FOR THE EFFECT OF EVOLUTIONARY STATUS ON CARBON ABUNDANCES.” The Astrophysical Journal 797, no. 1 (November 20, 2014): 21. © 2014 The American Astronomical Societyen_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Physicsen_US
dc.contributor.departmentMIT Kavli Institute for Astrophysics and Space Researchen_US
dc.contributor.mitauthorFrebel, Anna L.en_US
dc.relation.journalThe Astrophysical Journalen_US
dc.eprint.versionFinal published versionen_US
dc.type.urihttp://purl.org/eprint/type/JournalArticleen_US
eprint.statushttp://purl.org/eprint/status/PeerRevieweden_US
dspace.orderedauthorsPlacco, Vinicius M.; Frebel, Anna; Beers, Timothy C.; Stancliffe, Richard J.en_US
dc.identifier.orcidhttps://orcid.org/0000-0002-2139-7145
mit.licensePUBLISHER_POLICYen_US
mit.metadata.statusComplete


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