J/MNRAS/437/1609ivo://CDS.VizieR/J/MNRAS/437/1609doi:10.26093/cds/vizier.74371609CDSMarino A.F.Milone A.P.Przybilla N.Bergemann M.Lind K.Asplund M.,Cassisi S.Catelan M.Casagrande L.Valcarce A.A.R.Bedin L.R.,Cortes C.D'antona F.Jerjen H.Piotto G.Schlesinger K.Zoccali M.,Angeloni R.2024-08-07T20:12:19Z2015-01-16T09:08:02ZCDS support team

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

cds-question@unistra.frglobular-star-clustershorizontal-branch-starschemical-abundancesWe present an abundance analysis of 96 horizontal branch (HB) stars in NGC 2808, a globular cluster exhibiting a complex multiple stellar population pattern. These stars are distributed in different portions of the HB and cover a wide range of temperature. By studying the chemical abundances of this sample, we explore the connection between HB morphology and the chemical enrichment history of multiple stellar populations. For stars lying on the red HB, we use GIRAFFE and UVES spectra to determine Na, Mg, Si, Ca, Sc, Ti, Cr, Mn, Fe, Ni, Zn, Y, Ba and Nd abundances. For colder, blue HB stars, we derive abundances for Na, primarily from GIRAFFE spectra. We were also able to measure direct non-local thermodynamic equilibrium He abundances for a subset of these blue HB stars with temperature higher than ~9000K. Our results show that: (i) HB stars in NGC 2808 show different content in Na depending on their position in the colour-magnitude diagram, with blue HB stars having higher Na than red HB stars; (ii) the red HB is not consistent with a uniform chemical abundance, with slightly warmer stars exhibiting a statistically significant higher Na content; and (iii) our subsample of blue HB stars with He abundances shows evidence of enhancement with respect to the predicted primordial He content by {Delta}Y=+0.09+/-0.01+/-0.05 (internal plus systematic uncertainty). Our results strongly support theoretical models that predict He enhancement among second-generation(s) stars in globular clusters and provide observational constraints on the second-parameter governing HB morphology.2014MNRAS.437.1609Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/437/1609CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+AS/84/59 : Photometry of NGC 2808 (Ferraro+, 1990)J/ApJ/562/368 : UV photometry in NGC 2808 (Brown+, 2001)J/A+A/413/343 : RGB stars in NGC 2808 (Cacciari+, 2004)J/A+A/417/597 : Radial velocities in 4 globular clusters (Recio-Blanco+, 2004)J/ApJ/625/156 : FUV-NUV observations of NGC 2808 (Dieball+, 2005)J/AJ/131/1766 : Abundances and equivalent widths in NGC 2808 (Carretta, 2006)J/A+A/480/397 : XMM observations of NGC 2808 and NGC 4372 (Servillat+, 2008)J/A+A/490/641 : X-ray sources toward NGC 2808 (Servillat+, 2008)J/A+A/528/A127 : Radial velocities in the globular NGC 2808 (Moni Bidin+, 2011)J/A+A/534/A123 : Horizontal branch stars in NGC 2808 (Gratton+, 2011)J/A+A/542/A129 : NGC 2808 central kinematics (Luetzgendorf+, 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/437/1609https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/437/1609http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/437/1609https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/437/1609https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/437/1609http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/437/1609GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/437/1609/table1 (*Basic data for the analysed UVES and GIRAFFE stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/437/1609/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/437/1609/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/437/1609/table1?GETtext/xml+votable180.050000true138.01836667-64.846572780.0055555555555555566/37294 376363.322582951404819e-19 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/437/1609?format=asciidefaultJ/MNRAS/437/1609/table1*Basic data for the analysed UVES and GIRAFFE starsInstInstrument (GIRAFFE or UVES)meta.id;instrcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[231/23610] Star ID numbermeta.id;meta.mainintprimaryASimbad column added by the CDSmeta.ref.urlcharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainVmagV magnitudemagphot.mag;em.opt.VfloatB-VoOriginal B-V colour indexmagphot.color;em.opt.B;em.opt.VfloatB-VcCorrected B-V colour indexmagphot.color;em.opt.B;em.opt.VfloatRV[-15/124] Radial velocitykm/sphys.veloc;pos.heliocentricfloat2MASS2MASS identification (HHMMSSss+DDMMSSs)meta.idcharTypeStar type (BHB, RHB, F or GJ) (1)src.classcharJ/MNRAS/437/1609/table2Atmospheric parameters from Fe lines, and Teff from photometry for the RHB stars observed with UVESrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[231/23610] Star Identification numbermeta.id;meta.mainintTeffEffective temperature from Fe lineKphys.temperature.effectiveintloggSurface gravity from Fe linelog(cm.s**-2)phys.gravityfloatvtMicroturbulent velocity from Fe linekm/sphys.velocfloatTeffAEffective temperature from photometry (Alonso)Kphys.temperature.effectiveintJ/MNRAS/437/1609/table3Atmospheric parameters and chemical abundances for the RHB stars and colder BHB stars observed with GIRAFFErecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[231/23610] Star Identification numbermeta.id;meta.mainintTeffEffective temperatureKphys.temperature.effectiveintloggsurface gravitylog(cm.s**-2)phys.gravityfloatvtMicroturbulent velocitykm/sphys.velocfloat[Fe/H]1? Abundance [Fe/H] from FeIlog(Sun)phys.abund.Fefloatnullable[Fe/H]2? Abundance [Fe/H] from FeIIlog(Sun)phys.abund.Fefloatnullable[Na/Fe]LTE abundance [Na/Fe]log(Sun)phys.abundfloat[Na/Fe]nNLTE abundance [Na/Fe]log(Sun)phys.abundfloate_[Na/Fe]? rms uncertainty on abundances [Na/Fe]log(Sun)stat.error;phys.abundfloatnullable[Si/Fe]? Abundance [Si/Fe]log(Sun)phys.abundfloatnullable[Ca/Fe]? Abundance [Ca/Fe]log(Sun)phys.abundfloatnullable[Ti/Fe]? Abundance [Ti/Fe]log(Sun)phys.abundfloatnullable[Mn/Fe]? Abundance [Mn/Fe]log(Sun)phys.abundfloatnullablee_[Mn/Fe]? rms uncertainty on abundance [Mn/Fe]log(Sun)stat.error;phys.abundfloatnullable[Ba/Fe]? Abundance [Ba/Fe]log(Sun)phys.abundfloatnullableTeffI? effective temperature from IRFM (Infra-Red Flux Method)Kphys.temperature.effectiveintnullableJ/MNRAS/437/1609/table4Atmospheric parameters and individual abundances, with the associated line-to-line scatter, for the RHB stars observed with UVESrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[231/23610] Star Identification numbermeta.id;meta.mainintTeffEffective temperatureKphys.temperature.effectiveintloggSurface gravitylog(cm.s**-2)phys.gravityfloatvtMicroturbulent velocitykm/sphys.velocfloat[Fe/H]Abundance [Fe/H]log(Sun)phys.abund.Fefloat[Fe/H]1Abundance [Fe/H]Ilog(Sun)phys.abund.Fefloate_[Fe/H]1rms uncertainty in abundance [Fe/H]Ilog(Sun)stat.error;phys.abund.Fefloat[Fe/H]2Abundace [Fe/H]IIlog(Sun)phys.abund.Fefloate_[Fe/H]2rms uncertainty in abundance [Fe/H]IIlog(Sun)stat.error;phys.abund.Fefloat[Na/Fe]LTE abundance [Na/Fe]log(Sun)phys.abundfloate_[Na/Fe]rms uncertainty on abundance [Na/Fe]LTElog(Sun)stat.error;phys.abundfloat[Na/Fe]nNLTE abundance [Na/Fe]log(Sun)phys.abundfloate_[Na/Fe]nrms uncertainty on abundance [Na/Fe]NLTElog(Sun)stat.error;phys.abundfloat[Mg/Fe]Abundance [Mg/Fe]log(Sun)phys.abundfloate_[Mg/Fe]rms uncertainty on abundance [Mg/Fe]log(Sun)stat.error;phys.abundfloat[Si/Fe]Abundance [Si/Fe]log(Sun)phys.abundfloate_[Si/Fe]rms uncertainty on abundance [Si/Fe]log(Sun)stat.error;phys.abundfloat[Ca/Fe]Abundance [Ca/Fe]log(Sun)phys.abundfloate_[Ca/Fe]rms uncertainty on abundance [Ca/Fe]log(Sun)stat.error;phys.abundfloat[Sc/Fe]Abundance [Ti/Fe]log(Sun)phys.abundfloate_[Sc/Fe]rms uncertainty on abundance [Sc/Fe]log(Sun)stat.error;phys.abundfloat[Ti/Fe]1Abundance [Ti/Fe]Ilog(Sun)phys.abundfloate_[Ti/Fe]1rms uncertainty on abundance [Ti/Fe]Ilog(Sun)stat.error;phys.abundfloat[Ti/Fe]2Abundance [Ti/Fe]IIlog(Sun)phys.abundfloate_[Ti/Fe]2rms uncertainty on abundance [Ti/Fe]IIlog(Sun)stat.error;phys.abundfloat[Cr/Fe]1Abundance [Mn/Fe]Ilog(Sun)phys.abundfloate_[Cr/Fe]1rms uncertainty on abundance [Cr/Fe]Ilog(Sun)stat.error;phys.abundfloat[Cr/Fe]2Abundance [Mn/Fe]IIlog(Sun)phys.abundfloate_[Cr/Fe]2rms uncertainty on abundance [Cr/Fe]IIlog(Sun)stat.error;phys.abundfloat[Ni/Fe]Abundance [Ni/Fe]log(Sun)phys.abundfloate_[Ni/Fe]rms uncertainty on abundance [Ni/Fe]log(Sun)stat.error;phys.abundfloat[Zn/Fe]Abundance [Zn/Fe]log(Sun)phys.abundfloate_[Zn/Fe]rms uncertainty on abundance [Zn/Fe]log(Sun)stat.error;phys.abundfloat[Y/Fe]Abundance [Y/Fe]log(Sun)phys.abundfloate_[Y/Fe]rms uncertainty on abundance [Y/Fe]log(Sun)stat.error;phys.abundfloat[Ba/Fe]2Abundance [Ba/Fe]IIlog(Sun)phys.abundfloate_[Ba/Fe]2rms uncertainty on abundance [Ba/Fe]IIlog(Sun)stat.error;phys.abundfloat[Nd/Fe]2Abundance [Nd/Fe]IIlog(Sun)phys.abundfloate_[Nd/Fe]2rms uncertainty on abundance [Nd/Fe]IIlog(Sun)stat.error;phys.abundfloatJ/MNRAS/437/1609/table6Atmospheric parameters, chemical abundances and line-to-line scatter (when applicable) for the BHB UVES starsIDID numbermeta.id;meta.mainintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTeffEffective temperatureKphys.temperature.effectiveintloggSurface gravitylog(cm.s**-2)phys.gravityfloatvtMicroturbulent velocitykm/sphys.velocfloat[Fe/H]2Abundance [Fe/H]log(Sun)phys.abund.Fefloate_[Fe/H]2rms uncertainty on abundance [Fe/H]log(Sun)stat.error;phys.abund.Fefloatl_[Na/Fe]nLimit flag on [Na/Fe]NLTEmeta.code.error;phys.abundchar[Na/Fe]nAbundance [Na/Fe]NLTElog(Sun)phys.abundfloat[Mg/Fe]Abundance [Mg/Fe]log(Sun)phys.abundfloate_[Mg/Fe]rms uncertainty on abundance [Mg/Fe]log(Sun)stat.error;phys.abundfloatJ/MNRAS/437/1609/table7Atmospheric parameters, EWs for the He line and He mass fractions for the BHB stars observed with GIRAFFErecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTypeStar typesrc.classcharIDID numbermeta.id;meta.mainintTeffEffective temperatureKphys.temperature.effectiveintloggSurface gravitylog(cm.s**-2)phys.gravityfloatvtMicroturbulent velocitykm/sphys.velocfloatEWHe equivalent widths (in m{AA})0.1pmspect.line.eqWidthfloatvsini[0/15] Rotational velocitykm/sphys.veloc.rotatintY[0.03/0.45] NLTE Y mass fractionphysfloatTeffH? HST effective temperatureKphys.temperature.effectiveintnullableloggH? HST surface gravitylog(cm.s**-2)phys.gravityfloatnullable