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Metal-poor Lithium-rich Giants in the Radial Velocity Experiment Survey

Ruchti, Gregory R; Fulbright, J.P.; Wyse, Rosemary F G; Gilmore, Gerard; Grebel, E.; Bienayme, O; Bland-Hawthorn, Joss; Freeman, Kenneth; Gibson, Bradley K; Munari, U; Navarro, J F; Parker, Quentin A

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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] < -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] ≲ -1.9), and have a Li abundance (in the form of7Li), 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) < 0.5, while two stars, with A(Li)∼1.7-1.8,...[Show more]

dc.contributor.authorRuchti, Gregory R
dc.contributor.authorFulbright, J.P.
dc.contributor.authorWyse, Rosemary F G
dc.contributor.authorGilmore, Gerard
dc.contributor.authorGrebel, E.
dc.contributor.authorBienayme, O
dc.contributor.authorBland-Hawthorn, Joss
dc.contributor.authorFreeman, Kenneth
dc.contributor.authorGibson, Bradley K
dc.contributor.authorMunari, U
dc.contributor.authorNavarro, J F
dc.contributor.authorParker, Quentin A
dc.date.accessioned2015-12-10T22:14:03Z
dc.identifier.issn0004-637X
dc.identifier.urihttp://hdl.handle.net/1885/50074
dc.description.abstractWe report the discovery of eight lithium-rich field giants found in a high-resolution spectroscopic sample of over 700 metal-poor stars ([Fe/H] < -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] ≲ -1.9), and have a Li abundance (in the form of7Li), 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) < 0.5, while two stars, with A(Li)∼1.7-1.8, 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 as7Be (which burns to7Li) is transported to the stellar surface via the Cameron-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.
dc.publisherIOP Publishing
dc.rightsAuthor/s retain copyright
dc.sourceAstrophysical Journal, The
dc.subjectKeywords: globular clusters: individual (M68, M3); stars: abundances; stars: late-type; stars: Population II
dc.titleMetal-poor Lithium-rich Giants in the Radial Velocity Experiment Survey
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume743
dc.date.issued2011
local.identifier.absfor020104 - Galactic Astronomy
local.identifier.ariespublicationu3356449xPUB197
local.type.statusPublished Version
local.contributor.affiliationRuchti, Gregory R, Johns Hopkins University
local.contributor.affiliationFulbright, J.P., Johns Hopkins University
local.contributor.affiliationWyse, Rosemary F G, Johns Hopkins University
local.contributor.affiliationGilmore, Gerard, University of Cambridge
local.contributor.affiliationGrebel, E., Universitat Heidelberg
local.contributor.affiliationBienayme, O, Observatoire de Strasbourg
local.contributor.affiliationBland-Hawthorn, Joss, University of Sydney
local.contributor.affiliationFreeman, Kenneth, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationGibson, Bradley K, University of Central Lancashire
local.contributor.affiliationMunari, U, INAF-Osservatorio Astronomico di Padova
local.contributor.affiliationNavarro, J F, University of Victoria
local.contributor.affiliationParker, Quentin A, Macquarie University
local.bibliographicCitation.issue2
local.bibliographicCitation.startpageA107
local.bibliographicCitation.lastpage14
local.identifier.doi10.1088/0004-637X/743/2/107
local.identifier.absseo970102 - Expanding Knowledge in the Physical Sciences
dc.date.updated2016-02-24T09:54:17Z
local.identifier.scopusID2-s2.0-83455229360
local.identifier.thomsonID000298178400009
dcterms.accessRightsOpen Access
CollectionsANU Research Publications

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