J/A+A/661/A153ivo://CDS.VizieR/J/A+A/661/A153doi:10.26093/cds/vizier.36610153CDSMucciarelli A.Monaco L.Bonifacio P.Salaris M.Deal M.Spite M.,Richard O.Lallement R.2022-11-13T16:58:12Z2022-05-27T12:03:40ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frgiant-starschemically-peculiar-starsradial-velocityvisible-astronomyThe surface lithium abundance A(Li) of warm metal-poor dwarf stars exhibits a narrow plateau down to [Fe/H]~-2.8dex, while at lower metallicities the average value drops by 0.3dex with a significant star-by-star scatter (called lithium meltdown). This behaviour is in conflict with predictions of standard stellar evolution models calculated with the initial A(Li) provided by the standard Big Bang nucleosynthesis. The lower red giant branch (LRGB) stars provide a complementary tool to understand the initial A(Li) distribution in metal-poor stars. We have collected a sample of high-resolution spectra of 58 LRGB stars spanning a range of [Fe/H] between ~-7.0dex and ~-1.3dex. The LRGB stars display an A(Li) distribution clearly different from that of the dwarfs, without signatures of a meltdown and with two distinct components: (a) a thin A(Li) plateau with an average A(Li)=~1.09+/-0.01dex ({sigma}=~0.07dex), and (b) a small fraction of Li-poor stars with A(Li) lower than ~0.7dex. The A(Li) distribution observed in LRGB stars can be reconciled with an initial abundance close to the cosmological value, by including an additional chemical element transport in stellar evolution models. The required efficiency of this transport allows us to match also the Spite plateau lithium abundance measured in the dwarfs. The emerging scenario is that all metal-poor stars formed with the same initial A(Li) but those that are likely the product of coalescence or that experienced binary mass transfer and show lower A(Li). We conclude that A(Li) in LRGB stars is qualitatively compatible with the cosmological A(Li) value and that the meltdown observed in dwarf stars does not reflect a real drop of the abundance at birth.2022A&A...661A.153Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/661/A153CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/661/A153https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/661/A153http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/661/A153https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/661/A153https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/661/A153http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/661/A153GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/661/A153/table2 (Main information on the used spectra)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/661/A153/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/661/A153/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/661/A153/table2?GETtext/xml+votable180.050000true263.173436423.73656250.0055555555555555566/2997 3712 6058 8328 8864 16115 16651 16666 17099 17101 17357 17420 17578 17642 19210 22205 23118 23192 25051 25574 25595 25678 25733 26242 26347 27170 31394 31427 32468 32889 33192 33470 33695 34069 34096 34115 34438 34593 34595 35009 35750 35803 36135 36583 40319 43360 44208 45353 45818 45825 46023 46155 46370 46860 46902 47556 48392 48734https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/661/A153?format=asciiOpticaldefaultJ/A+A/661/A153/table2Main information on the used spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharInstrInstrumentmeta.id;instrcharlambda1Starting wavelength0.1nmtime.start;em.wlintlambda2Ending wavelength0.1nmtime.end;em.wlintresolSpectral resolutionspect.resolutionintRV? Radial velocitykm/sphys.veloc;pos.heliocentricdoublenullablee_RV? Uncertainty on radial velocitykm/sstat.errorfloatnullableIDProgram Identification Numbermeta.idcharPIPrincipal Investigatorobs.observercharSimbadNameSimbad column added by the CDSmeta.idcharnullable_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main