J/MNRAS/444/1812ivo://CDS.VizieR/J/MNRAS/444/1812doi:10.26093/cds/vizier.74441812CDSMucciarelli A.Salaris M.Bonifacio P.Monaco L.Villanova S.2024-08-10T20:18:40Z2015-09-09T09:20:30ZCDS support team

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

cds-question@unistra.frglobular-star-clusterschemical-abundancesgiant-starsThe cosmological Li problem is the observed discrepancy between Li abundance (A(Li)) measured in Galactic dwarf, old and metal-poor stars (traditionally assumed to be equal to the initial value A(Li)_0_), and that predicted by standard big bang nucleosynthesis (BBN) calculations (A(Li)_BBN_). Here, we attack the Li problem by considering an alternative diagnostic, namely the surface Li abundance of red giant branch stars that in a colour-magnitude diagram populate the region between the completion of the first dredge-up and the red giant branch bump. We obtained high-resolution spectra with the FLAMES facility at the Very Large Telescope for a sample of red giants in the globular cluster M54, belonging to the Sagittarius dwarf galaxy. We obtain A(Li)=0.93+/-0.11dex, translating - after taking into account the dilution due to the dredge-up - to initial abundances (A(Li)_0_) in the range 2.35-2.29 dex, depending on whether or not atomic diffusion is considered. This is the first measurement of Li in the Sagittarius galaxy and the more distant estimate of A(Li)_0_ in old stars obtained so far. The A(Li)_0_ estimated in M54 is lower by ~0.35dex than A(Li)_BBN_, hence incompatible at a level of ~3{sigma}. Our result shows that this discrepancy is a universal problem concerning both the Milky Way and extragalactic systems. Either modifications of BBN calculations, or a combination of atomic diffusion plus a suitably tuned additional mixing during the main sequence, need to be invoked to solve the discrepancy.2014MNRAS.444.1812Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/444/1812CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/109/1086 : VI Photometry in M54 and Sgr Dwarf Galaxy (Sarajedini+ 1995)J/AJ/118/1245 : Elemental abundances in five stars in M54 (Brown+, 1999)J/AJ/119/1760 : M54 and Sgr dSph VI photometry (Layden+, 2000)J/AJ/140/1500 : RR Lyrae variables in central region of M54 (Montiel+, 2010)J/MNRAS/406/329 : Variable stars in M54 (Sollima+, 2010)J/A+A/520/A95 : Abundances of red giants in M54 and Sgr dSph (Carretta+ 2010)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/444/1812https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/444/1812http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/444/1812https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/444/1812https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/444/1812http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/444/1812GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/444/1812/table1 (Identification numbers, coordinates, effective temperature, surface gravity, radial velocity, [Fe/H] and [Na/Fe] abundances)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/444/1812/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/444/1812/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/444/1812/table1?GETtext/xml+votable180.050000true283.79483028-30.499050.0055555555555555566/48035 48041https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/444/1812?format=asciidefaultJ/MNRAS/444/1812/table1Identification numbers, coordinates, effective temperature, surface gravity, radial velocity, [Fe/H] and [Na/Fe] abundancesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[6750/1043447] ID numbermeta.id;meta.mainintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainTeff[4627/5090] Effective temperatureKphys.temperature.effectiveintlogg[2.32/2.56] Surface gravitylog(cm.s**-2)phys.gravityfloatRV[102/178] Radial velocitykm/sphys.veloc;pos.heliocentricfloat[Fe/H][-2/0.52]? Metallicitylog(Sun)phys.abund.Zfloatnullable[Na/Fe][-1/0.77]? [Na/Fe] abundancelog(Sun)phys.abundfloatnullableMmb[M54 Sgr] indicates the membership to M54 or to Sgr dSphmeta.id.parentchar