Could The Ultra-Metal-Poor Stars Be Chemically Peculiar And Not Related To The First Stars?

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dc.contributor.utaustinauthorLambert, David L.en_US
dc.creatorVenn, Kim A.en_US
dc.creatorLambert, David L.en_US
dc.date.accessioned2016-04-28T19:41:38Z
dc.date.available2016-04-28T19:41:38Z
dc.date.issued2008-04en
dc.description.abstractChemically peculiar stars define a class of stars that show unusual elemental abundances due to stellar photospheric effects and not due to natal variations. In this paper, we compare the elemental abundance patterns of the ultra-metal-poor stars with metallicities [Fe/H]similar to-5 to those of a subclass of chemically peculiar stars. These include post-AGB stars, RV Tauri variable stars, and the Lambda Bootis stars, which range in mass, age, binarity, and evolutionary status, yet can have iron abundance determinations as low as [Fe/H]similar to-5. These chemical peculiarities are interpreted as due to the separation of gas and dust beyond the stellar surface, followed by the accretion of dust-depleted gas. Contrary to this, the elemental abundances in the ultra-metal-poor stars are thought to represent yields of the most metal-poor supernovae and, therefore, observationally constrain the earliest stages of chemical evolution in the universe. Detailed chemical abundances are now available for HE 1327-2326 and HE 0107-5240, the two extreme ultra-metal-poor stars in our Galaxy, and for HE 0557-4840, another ultra-metal-poor star found by the Hamburg/ESO survey. There are interesting similarities in their abundance ratios to those of the chemically peculiar stars; e. g., the abundances of the elements in their photospheres are related to the condensation temperature of that element. If these three stars are chemically peculiar, then their CNO abundances suggest true metallicities of [X/H] similar to-2 to -4. It is important to establish the nature of these stars, since they are used as tests of the early chemical evolution of the Galaxy.en_US
dc.description.departmentMcDonald Observatoryen_US
dc.description.sponsorshipNSERCen_US
dc.identifierdoi:10.15781/T2G538
dc.identifier.Filename2008_04_ultrametalpoor.pdfen_US
dc.identifier.citationVenn, K. A., and David L. Lambert. "Could the Ultra-Metal-poor Stars be Chemically Peculiar and Not Related to the First Stars?." The Astrophysical Journal, Vol. 677, No. 1 (Apr., 2008): 572.en_US
dc.identifier.doi10.1086/529069en_US
dc.identifier.issn0004-637Xen_US
dc.identifier.urihttp://hdl.handle.net/2152/35117
dc.language.isoEnglishen_US
dc.relation.ispartofen_US
dc.relation.ispartofserialAstrophysical Journalen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.rights.restrictionOpenen_US
dc.subjectearly universeen_US
dc.subjectstars : abundancesen_US
dc.subjectstars : chemically peculiaren_US
dc.subjectstars :en_US
dc.subjectindividual (he 1327-2326)en_US
dc.subjectlambda-bootis starsen_US
dc.subjecthigh-resolution spectroscopyen_US
dc.subjectrv tauri starsen_US
dc.subjectpost-agb starsen_US
dc.subjectabundance analysisen_US
dc.subjectmodel atmospheresen_US
dc.subjectcarbon-richen_US
dc.subjecthaloen_US
dc.subjectstarsen_US
dc.subjectnitrogen abundanceen_US
dc.subjectoxygen abundanceen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleCould The Ultra-Metal-Poor Stars Be Chemically Peculiar And Not Related To The First Stars?en_US
dc.typeArticleen_US

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