J/A+A/653/L8ivo://CDS.VizieR/J/A+A/653/L8doi:10.26093/cds/vizier.36539008CDSLatour M.Calamida A.Husser T.-O.Kamann S.Dreizler S.Brinchmann J.2024-09-02T20:00:58Z2021-09-20T08:00:26ZCDS support team

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

cds-question@unistra.frglobular-star-clustersmetallicityeffective-temperaturevisible-astronomyOmega Cen is a rare example of a globular cluster where the iron abundance of the stars spans more than one order of magnitude. Many spectroscopic investigations of its red-giant- and sub-giant- branches have revealed multiple peaks in the iron abundance distribution. The metallicity distribution of main-sequence (MS) stars is not well characterized yet, due to the faintness of the stars and lack of data. So far, almost all studies of MS stars are based on photometric measurements. Our goal is to investigate the metallicity distribution of a statistically significant sample of MS stars in Omega Cen. In particular, we aim at revisiting the metallicity difference between the red and blue MS of the cluster. We use MUSE spectra obtained for the central region of omega Cen to derive metallicities for ~4200 MS stars. We find that blue MS stars are on average ~0.1dex more metal-rich than their red counterparts. On the basis of this new estimate, we find that the two sequences can be fit on the Hubble Space Telescope color-magnitude diagram with two isochrones having the same global metallicity and age but a higher helium abundance for the blue MS, i.e. {DELTA}Y~<0.1. Furthermore, we determine the average metallicity of the five main populations along Omega Cen MS and these estimates are consistent with expectations from previous photometric studies.2021A&A...653L...8Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/653/L8CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/842/6 : Core of NGC 5139 astro-photometric catalog (Bellini+, 2017)J/ApJ/844/164 : NGC5139 HST astro-photometric analysis. III. (Bellini+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/653/L8https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/653/L8http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/653/L8https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/653/L8https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/653/L8http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/653/L8GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/653/L8/tableb1 (Atmospheric parameters for MS stars in omega Centauri)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/653/L8/tableb1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/653/L8/tableb1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/653/L8/tableb1?GETtext/xml+votable180.050000true201.65639167-47.456422220.0055555555555555566/43227https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/653/L8?format=asciiOpticaldefaultJ/A+A/653/L8/tableb1Atmospheric parameters for MS stars in omega Centauri[M/H]Metallicitylog(Sun)phys.abund.Zfloate_[M/H]Calibrated error on the metallicitylog(Sun)stat.error;phys.abundfloatSNRS/N of the spectrastat.snrfloatrMS[1]? 1 if included in our rMSmeta.codeintnullablebMS[1]? 1 if included in our bMSmeta.codeintnullableSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDStar ID, from Bellini et al., (2017, Cat. J/ApJ/842/6)meta.id;meta.mainintRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainTeffEffective temperatureKphys.temperature.effectiveinte_TeffCalibrated error on the effective temperatureKstat.error;phys.temperature.effectiveintloggSurface gravitylog(cm.s**-2)phys.gravityfloate_loggError on the surface gravitylog(cm.s**-2)stat.errorfloat