J/ApJ/726/L20ivo://CDS.VizieR/J/ApJ/726/L20doi:10.26093/cds/vizier.17269020CDSOriglia L.Rich R.M.Ferraro F.R.Lanzoni B.Bellazzini M.,Dalessandro E.Mucciarelli A.Valenti E.Beccari G.2012-09-29T16:37:20Z2012-09-12T09:47:26ZCDS support team

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

cds-question@unistra.frgiant-starschemical-abundancesradial-velocitystellar-associationsglobular-star-clustersWe present the chemical abundance analysis of 33 red giant stars belonging to the complex stellar system Terzan 5. We confirm the discovery of two stellar populations with distinct iron abundances: a relatively metal-poor component with [Fe/H]=-0.25+/-0.07rms and another component with [Fe/H]=+0.27+/-0.04rms, exceeding in metallicity any known Galactic globular cluster (GC). The two populations also show different [{alpha}/Fe] abundance ratios. The metal-poor component has an average [{alpha}/Fe]=+0.34+/-0.06rms, consistent with the canonical scenario for rapid enrichment by core collapse supernovae (SNe). The metal-rich component has [{alpha}/Fe]=+0.03+/-0.04rms, suggesting that the gas from which it formed was polluted by both type II and type Ia SNe on a longer timescale. Neither of the two populations shows evidence of the [Al/Fe] over [O/Fe] anti-correlation that is typically observed in Galactic GCs. Because these chemical abundance patterns are unique, we propose that Terzan 5 is not a true GC, but a stellar system with a much more complex history of star formation and chemical enrichment.2011ApJ...726L..20Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/726/L20CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIII/249 : Stellar radial velocities bibliographic catalog (Malaroda+, 2006)VII/151 : Structure Parameters of Galactic Globular Clusters (Webbink 1985)VII/103 : Galactic Globular Clusters (Monella 1985)VII/44 : Star Clusters Associations II. Globular Clusters (Ruprecht+ 1981)J/AJ/140/1043 : GCs in M31 and the Galaxy (van den Bergh+, 2010)J/PASP/121/1378 : Positions of variable stars in GCs (Samus+, 2009)J/AJ/133/1287 : JHK photometry of 24 Galactic GCs (Valenti+, 2007)J/AJ/133/99 : JHKs surface brightness of Galactic GCs. (Cohen+, 2007)J/AJ/130/2140 : Abundances and velocities in GCs (Pritzl+, 2005)J/ApJS/161/304 : Star clusters in the Milky Way and satellites (McLaughlin+,J/ApJ/590/797 : Parameters of galactic GCs (Van Den Bregh+, 2003)J/PAZh/29/253 : GCs as gravitational lenses (Bukhmastova, 2003)J/A+A/308/733 : NTT VI photometry in Terzan 5 (Ortolani+ 1996)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/726/L20https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/726/L20http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/726/L20https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/726/L20https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/726/L20http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/726/L20GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/726/L20/table1 (Stellar parameters and abundances for the sample of observed giants in Terzan 5)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/726/L20/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/726/L20/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/726/L20/table1?GETtext/xml+votable180.050000true267.0182525-24.778723330.0055555555555555566/28899 28905https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/726/L20?format=asciiOpticaldefaultJ/ApJ/726/L20/table1Stellar parameters and abundances for the sample of observed giants in Terzan 5SeqIndex numbermeta.id;meta.mainintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainTeff[3400/4500] Effective temperatureKphys.temperature.effectiveintlog(g)[0.5/2] Log of the surface gravitylog(cm.s**-2)phys.gravityfloatHRVHeliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricint[Fe/H]Log of the Fe/H number abundancelog(Sun)meta.idfloate_[Fe/H]Uncertainty in [Fe/H]log(Sun)stat.error;phys.abund.Fefloat[O/Fe]Log of the O/Fe number abundancelog(Sun)meta.idfloate_[O/Fe]Uncertainty in [O/Fe]log(Sun)stat.error;phys.abundfloat[Si/Fe]Log of the Si/Fe number abundancelog(Sun)meta.idfloate_[Si/Fe]Uncertainty in [Si/Fe]log(Sun)stat.error;phys.abundfloat[Mg/Fe]Log of the Mg/Fe number abundancelog(Sun)meta.idfloate_[Mg/Fe]Uncertainty in [Mg/Fe]log(Sun)stat.error;phys.abundfloat[Ca/Fe]Log of the Ca/Fe number abundancelog(Sun)meta.idfloate_[Ca/Fe]Uncertainty in [Ca/Fe]log(Sun)stat.error;phys.abundfloat[Ti/Fe]Log of the Ti/Fe number abundancelog(Sun)meta.idfloate_[Ti/Fe]Uncertainty in [Ti/Fe]log(Sun)stat.error;phys.abundfloat[Al/Fe]Log of the Al/Fe number abundancelog(Sun)phys.abundfloate_[Al/Fe]Uncertainty in [Al/Fe]log(Sun)stat.error;phys.abundfloat[C/Fe]Log of the C/Fe number abundancelog(Sun)meta.idfloate_[C/Fe]Uncertainty in [C/Fe]log(Sun)stat.error;phys.abundfloat