J/A+A/501/519ivo://CDS.VizieR/J/A+A/501/519doi:10.26093/cds/vizier.35010519CDSBonifacio P.Spite M.Cayrel R.Hill V.Spite F.Francois P.Plez B.,Ludwig H.-G.Caffau E.Molaro P.Depagne E.Andersen J.Barbuy B.,Beers T.C.Nordstroem B.Primas F.2020-01-29T09:06:31Z2009-09-30T22:38:33ZCDS support team

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

cds-question@unistra.frhalo-starschemically-peculiar-starsgiant-starschemical-abundancesradial-velocityline-intensitiespopulation-ii-starsThe detailed chemical abundances of extremely metal-poor (EMP) stars are key guides to understanding the early chemical evolution of the Galaxy. Most existing data, however, treat giant stars that may have experienced internal mixing later. We aim to compare the results for giants with new, accurate abundances for all observable elements in 18 EMP turnoff stars. VLT/UVES spectra at ~45000 and S/N ~130 per pixel (330-1000nm) are analysed with OSMARCS model atmospheres and the TURBOSPECTRUM code to derive abundances for C, Mg, Si, Ca, Sc, Ti, Cr, Mn, Co, Ni, Zn, Sr, and Ba. For Ca, Ni, Sr, and Ba, we find excellent consistency with our earlier sample of EMP giants, at all metallicities. However, our abundances of C, Sc, Ti, Cr, Mn and Co are ~0.2dex larger than in giants of similar metallicity. Mg and Si abundances are ~0.2dex lower (the giant [Mg/Fe] values are slightly revised), while Zn is again ~0.4dex higher than in giants of similar [Fe/H] (6 stars only). For C, the dwarf/giant discrepancy could possibly have an astrophysical cause, but for the other elements it must arise from shortcomings in the analysis. Approximate computations of granulation (3D) effects yield smaller corrections for giants than for dwarfs, but suggest that this is an unlikely explanation, except perhaps for C, Cr, and Mn. NLTE computations for Na and Al provide consistent abundances between dwarfs and giants, unlike the LTE results, and would be highly desirable for the other discrepant elements as well. Meanwhile, we recommend using the giant abundances as reference data for Galactic chemical evolution models.2009A&A...501..519Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/501/519CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/403/1105 : Extremely metal-poor giants equivalent widths (Francois+ 2003)J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/501/519https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/501/519http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/501/519https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/501/519https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/501/519http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/501/519GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/501/519/table7 (Radial velocities of programme giant stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/501/519/table7?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/501/519/table7?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/501/519/table7?GETtext/xml+votable180.050000true7.8204789-16.79466470.005555555555555556Cone search capability for table J/A+A/501/519/table1 (Adopted model atmosphere parameters for unevolved stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/501/519/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/501/519/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/501/519/table1?GETtext/xml+votable180.050000true210.226975622.77835750.0055555555555555566/8205 8228 8328 8864 8930 16540 16549 16587 16795 16821 17343 17788 19017 19070 19210-19211 19903 22662 26457 28097 31395 31585 32352 33470 33515 33642 34574 34751 35532 35561 35731 35736 35784 36705 36737 45470 45694 45797 45808 45818 45825 46565 46699 46796 46958 47556 48221 48501 48517 48526 48798 48824https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/501/519?format=asciidefaultJ/A+A/501/519/table7Radial velocities of programme giant starsSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1,35] sequential number of the starmeta.recordintNameStar namemeta.id;meta.maincharDate? Observation date (1)time.epoch;obsnullableMJD? Modified Julian date (JD-2400000.5) of observation (1)dtime.epochdoublenullableRVBarycentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloat_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.mainJ/A+A/501/519/table1Adopted model atmosphere parameters for unevolved starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/19] Sequential number of unevolved starsmeta.recordintprimaryNameStar namemeta.id;meta.maincharTeffEffective temperatureKphys.temperature.effectiveintloggSurface gravitylog(cm.s**-2)phys.gravityfloatVtMicroturbulent velocitykm/sphys.velocfloat[Fe/H]Metallicityphys.abund.ZfloatRemRemarksmeta.notecharSimbadSimbad column added by the CDSmeta.ref.urlchar_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.mainJ/A+A/501/519/ewEquivalent widths for unevolved starsIonIon identificationphys.atmol.ionStagecharn_AB[*] not used for mean (2)meta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1,19] Sequential numbermeta.recordintlambdaWavelength of the linenmem.wl;spect.linedoublechiExcitation potentialeVphys.atmol.excitationfloatloggfLogarithm of the oscillator strengthphys.atmol.oscStrengthfloatEW? Equivalent widthpmspect.line.eqWidthfloatnullablen_EW[s] abundance from spectrum synthesis (1)meta.notecharl_ABLimit flag on ABmeta.code.errorcharAB? Abundance log(N/H)+12phys.abundfloatnullable