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dc.contributor.authorYong, David
dc.contributor.authorNorris, John
dc.contributor.authorBessell, Michael S.
dc.contributor.authorAsplund, Martin
dc.contributor.authorBeers, Timothy C.
dc.contributor.authorBarklem, Paul S.
dc.contributor.authorFrebel, Anna
dc.contributor.authorRyan, Sean G.
dc.date.accessioned2013-08-05T09:48:13Z
dc.date.available2013-08-05T09:48:13Z
dc.date.issued2013-01
dc.identifier.citationYong , D , Norris , J , Bessell , M S , Asplund , M , Beers , T C , Barklem , P S , Frebel , A & Ryan , S G 2013 , ' The Most Metal-poor Stars. II : Chemical Abundances of 190 Metal-poor Stars Including 10 New Stars with [Fe/H] <= -3.5 ' , The Astrophysical Journal , vol. 762 , 26 . https://doi.org/10.1088/0004-637X/762/1/26
dc.identifier.issn0004-637X
dc.identifier.otherPURE: 2153307
dc.identifier.otherPURE UUID: c5321d7f-f665-4648-930f-49a8b6abe1b1
dc.identifier.otherScopus: 84871277951
dc.identifier.otherORCID: /0000-0001-9069-5122/work/30501321
dc.identifier.urihttp://hdl.handle.net/2299/11288
dc.description.abstractWe present a homogeneous chemical abundance analysis of 16 elements in 190 metal-poor Galactic halo stars (38 program and 152 literature objects). The sample includes 171 stars with [Fe/H] <= -2.5, of which 86 are extremely metal poor, [Fe/H] <= -3.0. Our program stars include 10 new objects with [Fe/H] <= -3.5. We identify a sample of "normal" metal-poor stars and measure the trends between [X/Fe] and [Fe/H], as well as the dispersion about the mean trend for this sample. Using this mean trend, we identify objects that are chemically peculiar relative to "normal" stars at the same metallicity. These chemically unusual stars include CEMP-no objects, one star with high [Si/Fe], another with high [Ba/Sr], and one with unusually low [X/Fe] for all elements heavier than Na. The Sr and Ba abundances indicate that there may be two nucleosynthetic processes at lowest metallicity that are distinct from the main r-process. Finally, for many elements, we find a significant trend between [X/Fe] versus T eff, which likely reflects non-LTE and/or three-dimensional effects. Such trends demonstrate that care must be exercised when using abundance measurements in metal-poor stars to constrain chemical evolution and/or nucleosynthesis predictions.en
dc.language.isoeng
dc.relation.ispartofThe Astrophysical Journal
dc.subjectearly universe, Galaxy: formation, Galaxy: halo, nuclear reactions, nucleosynthesis, abundances, stars: abundances
dc.titleThe Most Metal-poor Stars. II : Chemical Abundances of 190 Metal-poor Stars Including 10 New Stars with [Fe/H] <= -3.5en
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.contributor.institutionScience & Technology Research Institute
dc.contributor.institutionCentre for Astrophysics Research
dc.description.statusPeer reviewed
rioxxterms.versionAM
rioxxterms.versionofrecordhttps://doi.org/10.1088/0004-637X/762/1/26
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue


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