J/ApJ/928/L11ivo://CDS.VizieR/J/ApJ/928/L11doi:10.26093/cds/vizier.19289011CDSAlvarez Garay D.A.Mucciarelli A.Lardo C.Bellazzini M.Merle T.2024-11-06T20:24:37Z2024-04-05T13:48:35ZCDS support team

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

cds-question@unistra.frchemical-abundancesvisible-astronomyspectroscopyradial-velocityWe present [K/Fe] abundance ratios for a sample of 450 stars in {omega} Centauri, using high-resolution spectra acquired with the multiobject spectrograph FLAMES@VLT. Abundances for Fe, Na, and Mg were also derived. We detected intrinsic K variations in the analyzed stars. Moreover, [K/Fe] shows a significant correlation with [Na/Fe] and an anticorrelation with [Mg/Fe]. The presence of a clear-cut Mg-K anticorrelation makes {omega} Centauri the third stellar system, after NGC 2419 and NGC 2808, hosting a subpopulation of stars with [Mg/Fe]<0.0dex, K-enriched in the case of {omega} Centauri by ~0.3dex with respect to Mg-rich stars ([Mg/Fe]>0.0dex). The correlation/anticorrelation between K and other light elements involved in chemical anomalies supports the idea that the spread in [K/Fe] can be associated with the same self-enrichment process typical of globular clusters. We suggest that significant variations in K abundances perhaps can be found in the most massive and/or metal-poor globular clusters as a manifestation of an extreme self-enrichment process. Theoretical models face problems explaining K production in globular clusters. Indeed, models where asymptotic giant branch stars are responsible for the Mg-K anticorrelation only qualitatively agree with the observations. Finally, we discovered a peculiar star with an extraordinary K overabundance ([K/Fe]=+1.60dex) with respect to the other stars with similar [Mg/Fe]. We suggest that this K-rich star could be formed from the pure ejecta of AGB stars before dilution with pristine material.2022ApJ...928L..11Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/928/L11CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/350 : Gaia EDR3 (Gaia Collaboration, 2020)I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)J/A+A/505/117 : Abundances of red giants in 15 GCs (Carretta+, 2009)J/ApJ/705/328 : Abundance measurements in Sculptor dSph (Kirby+, 2009)J/ApJ/722/1373 : {omega} Centauri giants abundances (Johnson+, 2010)J/ApJ/731/64 : Spectroscopy of 300 RGBs in {omega} Cen (Marino+, 2011)J/ApJ/760/86 : Equivalent widths for 13 NGC2419 RGB stars (Cohen+, 2012)J/MNRAS/450/815 : Red giants in NGC 5286 (Marino+, 2015)J/AJ/149/153 : Abundances of red giants in 10 GCs (Meszaros+, 2015)J/A+A/600/A104 : K abundance in 3 globular clusters (Mucciarelli+, 2017)J/A+A/601/A112 : GES iDR4 Mg-Al anticorrelation in GCs (Pancino+, 2017)J/MNRAS/478/1520 : Milky Way globular clusters data (Baumgardt+, 2018)J/A+A/616/A10 : Open clusters GaiaDR2 HR diagrams (Gaia Collaboration, 2018)J/A+A/627/A177 : Non-LTE analysis of K I in late-type stars (Reggiani+, 2019)J/MNRAS/492/1641 : APOGEE southern GCs with the BACCHUS code (Meszaros+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/928/L11https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/928/L11http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/928/L11https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/928/L11https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/928/L11http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/928/L11GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/928/L11/table1 (Data for the analysed targets in {omega} Centauri)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/928/L11/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/928/L11/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/928/L11/table1?GETtext/xml+votable180.050000true201.7877147-47.39397470.0055555555555555566/43225 432271.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/928/L11?format=asciiOpticaldefaultJ/ApJ/928/L11/table1Data for the analysed targets in {omega} CentauriSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDIdentifier (1)meta.id;meta.maincharGmag[10.69/14.4] Gaia EDR3 G band magnitudemagphot.mag;em.optfloatRVel[191/277] Radial velocitykm/sphys.veloc;pos.heliocentricfloatTeff[3934/5283] Effective temperatureKphys.temperature.effectiveinte_Teff[85/147] Uncertainty in TeffKstat.error;phys.temperature.effectiveintlog(g)[0.4/2.5] log surface gravitylog(cm.s**-2)phys.gravityfloatvt[1.5/2.1] Microturbulent velocitykm/sphys.velocfloat[Fe/H][-2.2/-0.5] log Fe/H abundance ratiophys.abund.Fe;arith.ratiofloate_[Fe/H][0.05/0.2] Uncertainty in [Fe/H]stat.error;phys.abund.Fefloat[Na/Fe][-0.42/0.6]? log Na/Fe abundance ratiophys.abundfloatnullablee_[Na/Fe][0.03/0.2]? Uncertainty in [Na/Fe]stat.error;phys.abundfloatnullable[Mg/Fe][-0.5/0.7]? log Mg/Fe abundance ratiophys.abundfloatnullablee_[Mg/Fe][0.02/0.21]? Uncertainty in [Mg/Fe]stat.error;phys.abundfloatnullable[K/Fe][-0.2/1.6] log K/Fe abundance ratiophys.abundfloate_[K/Fe][0.05/0.2] Uncertainty in [K/Fe]stat.error;phys.abundfloatJ10Display data from Johnson+ 2010, J/ApJ/722/1373meta.ref.urlintnullableM11Display data from Marino+ 2011, J/ApJ/731/64meta.ref.urlintnullable_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.main