J/A+A/490/625ivo://CDS.VizieR/J/A+A/490/625doi:10.26093/cds/vizier.34900625CDSMarino A.F.Villanova S.Piotto G.Milone A.P.Momany Y.Bedin L.R.,Medling A.M.2017-06-22T14:28:24Z2008-12-20T22:28:16ZCDS support team

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

cds-question@unistra.frglobular-star-clustersspectroscopychemical-abundancesWe present abundance analysis based on high resolution spectra of 105 isolated red giant branch (RGB) stars in the Galactic Globular Cluster NGC 6121 (M4). The data have been collected with FLAMES+UVES, at the ESO/VLT@UT2 telescope. Spectroscopic data were coupled with high precision wide-field UBVI_C photometry from WFI@2.2m telescope and infrared JHK photometry from 2MASS. We derived an average [Fe/H]=-1.07+/-0.01, and an {alpha} enhancement of [{alpha}/Fe]=+0.39+/-0.05dex (internal errors). We confirm the presence of an extended Na-O anticorrelation, and find two distinct groups of stars with significantly different Na and O content. We find no evidence of a Mg-Al anticorrelation. By coupling our results with previous studies on the CN band strength, we find that the CN strong stars have higher Na and Al content and are more O depleted than the CN weak ones. The two groups of Na-rich, CN-strong and Na-poor, CN-weak stars populate two different regions along the RGB. In the U vs. U-B color magnitude diagram the RGB spread is present from the base of the RGB to the RGB-tip. Apparently, both spectroscopic and photometric results imply the presence of two stellar populations in M4. We briefly discuss the possible origin of these populations.2008A&A...490..625Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/490/625CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/443/124 : Radial Velocities of Stars in M4 (Peterson+ 1995)J/PAZh/22/847 : Identification and coordinates in M4 (Shokin+, 1996)J/AJ/114/189 : M 4 CCD photometry (Alcaino+, 1997)J/ApJS/120/265 : HST photometry of M4 (Ibata+, 1999)J/AJ/127/2771 : HST proper-motions of M4 main-sequence stars (Richer+, 2004)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/490/625https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/490/625http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/490/625https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/490/625https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/490/625http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/490/625GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/490/625/results (Results: atmospheric parameters, photometry, and chemical abundances)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/490/625/results?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/490/625/results?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/490/625/results?GETtext/xml+votable180.050000true245.81007361-26.601536940.0055555555555555566/429558.650015785639275e-20 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/490/625?format=asciiOpticaldefaultJ/A+A/490/625/resultsResults: atmospheric parameters, photometry, and chemical abundancesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStar[5359/45895] Star identification numbermeta.id;meta.mainintRAJ2000Right ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainTeffEffective temperatureKphys.temperature.effectiveintloggSurface gravitylog(cm.s**-2)phys.gravityfloatVtMicroturbulent velocitykm/sphys.velocfloatUmag? Johnson U magnitudemagphot.mag;em.opt.UfloatnullableBmag? Johnson B magnitudemagphot.mag;em.opt.BfloatnullableVmag? Johnson V magnitudemagphot.mag;em.opt.VfloatnullableIcmag? Cousisn I magnitudemagphot.mag;em.opt.IfloatnullableJmag? 2MASS J magnitudemagphot.mag;em.IR.JfloatnullableHmag? 2MASS H magnitudemagphot.mag;em.IR.HfloatnullableKmag? 2MASS K magnitudemagphot.mag;em.IR.Kfloatnullable[Fe/HI]Abundance ratio [Fe/HI]log(Sun)phys.abund.Fe;arith.ratiofloat[O/Fe]? Abundance ratio [O/Fe]log(Sun)phys.abund;arith.ratiofloatnullable[Na/Fe]Abundance ratio [Na/Fe]log(Sun)phys.abund;arith.ratiofloat[Mg/Fe]Abundance ratio [Mg/Fe]log(Sun)phys.abund;arith.ratiofloat[Al/Fe]? Abundance ratio [Al/Fe]log(Sun)phys.abund;arith.ratiofloatnullable[Si/Fe]Abundance ratio [Si/Fe]log(Sun)phys.abund;arith.ratiofloat[Ca/Fe]Abundance ratio [Ca/Fe]log(Sun)phys.abund;arith.ratiofloat[Ti/FeI]Abundance ratio [Ti/FeI]log(Sun)phys.abundfloat[Ti/FeII]Abundance ratio [Ti/FeII]log(Sun)phys.abundfloat[Cr/Fe]Abundance ratio [Cr/Fe]log(Sun)phys.abund;arith.ratiofloat[Ni/Fe]Abundance ratio [Ni/Fe]log(Sun)phys.abund;arith.ratiofloat[Ba/FeII]? Abundance ratio [Ba/FeII]log(Sun)phys.abundfloatnullable