Metal-poor lithium-rich giants in the radial velocity experiment survey

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dc.creator Ruchti, Gregory R.
dc.creator Fulbright, Jon P.
dc.creator Wyse, Rosemary F. G.
dc.creator Gilmore, Gerard F.
dc.creator Grebel, Eva K.
dc.creator Bienayme, Olivier
dc.creator Bland-Hawthorn, Joss
dc.creator Freeman, Ken C.
dc.creator Gibson, Brad K.
dc.creator Munari, Ulisse
dc.date.accessioned 2018-04-27T19:08:12Z
dc.date.available 2018-04-27T19:08:12Z
dc.date.issued 2011-12-20
dc.identifier.issn 0004-637X
dc.identifier.uri http://library2.smu.ca/handle/01/27486
dc.description Publisher's Version/PDF
dc.description.abstract We report the discovery of eight lithium-rich field giants found in a high-resolution spectroscopic sample of over 700 metal-poor stars ([Fe/H] &lt; &minus;0.5) selected from the Radial Velocity Experiment survey. The majority of the Li-rich giants in our sample are very metal-poor ([Fe/H]&nbsp;≲ &minus;1.9), and have a Li abundance (in the form of <sup>7</sup>Li), A(Li) = log(n(Li)/n(H)) + 12, between 2.30 and 3.63, well above the typical upper red giant branch (RGB) limit, A(Li) &lt; 0.5, while two stars, with A(Li) &sim; 1.7&ndash;1.8, show similar lithium abundances to normal giants at the same gravity. We further included two metal-poor, Li-rich globular cluster giants in our sample, namely the previously discovered M3-IV101 and newly discovered (in this work) M68-A96. This comprises the largest sample of metal-poor Li-rich giants to date. We performed a detailed abundance analysis of all stars, finding that the majority of our sample stars have elemental abundances similar to that of Li-normal halo giants. Although the evolutionary phase of each Li-rich giant cannot be definitively determined, the Li-rich phase is likely connected to extra mixing at the RGB bump or early asymptotic giant branch that triggers cool bottom processing in which the bottom of the outer convective envelope is connected to the H-burning shell in the star. The surface of a star becomes Li-enhanced as <sup>7</sup>Be (which burns to <sup>7</sup>Li) is transported to the stellar surface via the Cameron&ndash;Fowler mechanism. We discuss and discriminate among several models for the extra mixing that can cause Li production, given the detailed abundances of the Li-rich giants in our sample. en_CA
dc.language.iso en en_CA
dc.publisher IOP Publishing Limited en_CA
dc.relation.uri https://dx.doi.org/10.1088/0004-637X/743/2/107
dc.rights Article is made available in accordance with the publisher’s policy and is subject to copyright law. Please refer to the publisher’s site. Any re-use of this article is to be in accordance with the publisher’s copyright policy. This posting is in no way granting any permission for re-use to the reader/user.
dc.subject.lcsh Stars -- Globular clusters
dc.subject.lcsh Cosmic abundances
dc.subject.lcsh Metal-poor stars
dc.subject.lcsh Lithium -- Isotopes
dc.subject.lcsh Cool stars
dc.title Metal-poor lithium-rich giants in the radial velocity experiment survey en_CA
dc.type Text en_CA
dcterms.bibliographicCitation Astrophysical Journal 743(2), 107. (2011) en_CA


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Article is made available in accordance with the publisher’s policy and is subject to copyright law. Please refer to the publisher’s site. Any re-use of this article is to be in accordance with the publisher’s copyright policy. This posting is in no way granting any permission for re-use to the reader/user.
 
Published Version: https://dx.doi.org/10.1088/0004-637X/743/2/107
 
 

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