J/ApJ/846/23ivo://CDS.VizieR/J/ApJ/846/23doi:10.26093/cds/vizier.18460023CDSO'Malley E.M.Knaizev A.McWilliam A.Chaboyer B.2018-08-16T06:24:39Z2018-05-25T09:44:23ZCDS support team

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

cds-question@unistra.frgiant-starschemical-abundancesvisible-astronomyspectroscopyradial-velocityline-intensitiesWe obtain high-resolution spectra of nine red giant branch stars in NGC 6681 and perform the first detailed abundance analysis of stars in this cluster. We confirm cluster membership for these stars based on consistent radial velocities of 214.5+/-3.7km/s and find a mean [Fe/H]=-1.63+/-0.07dex and [{alpha}/Fe]=0.42+/-0.11dex. Additionally, we confirm the existence of a Na-O anti-correlation in NGC 6681 and identify two populations of stars with unique abundance trends. With the use of HST photometry from Sarajedini+ (2007AJ....133.1658S) and Piotto+ (2015AJ....149...91P) we are able to identify these two populations as discrete sequences in the cluster CMD. Although we cannot confirm the nature of the polluter stars responsible for the abundance differences in these populations, these results do help put constraints on possible polluter candidates.2017ApJ...846...23Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/846/23CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/hst : HST Archived Exposures Catalog (STScI, 2007)III/184 : 3rd Bibliog. Cat. of Stellar Radial Vel. (Barbier-Brossat+, 1994)VII/195 : Globular Clusters in the Milky Way (Harris, 1996)VII/271 : Properties of Galactic Globular Clusters (Francis+, 2014)J/AJ/109/218 : Catalogue of globular cluster profiles (Trager+ 1995)J/A+A/356/238 : Atmospheric param. in metal-poor stars. III. (Carretta+ 2000)J/A+A/359/347 : Reddening in open and globular clusters (Dutra+, 2000)J/AJ/120/1841 : Abundances & Kinematics of Halo & Disk Stars (Fulbright 2000)J/A+AS/145/451 : Nearby globular clusters photometric cat. (Rosenberg+, 2000)J/A+A/404/187 : Equivalent widths for metal-poor stars (Gratton+, 2003)J/A+A/435/657 : Equivalent widths of 5 giants in 47 Tuc (Alves-Brito+, 2005)J/AJ/131/1766 : Abundances and equivalent widths in NGC 2808 (Carretta, 2006)J/ApJ/638/1018 : Equivalent widths for giant stars in M13 & M71 (Yong+, 2006)J/A+A/490/625 : Abundances of NGC 6121 red giants (Marino+, 2008)J/A+A/505/139 : Abundances of red giants in 17 GCs (Carretta+, 2009)J/A+A/505/117 : Abundances of red giants in 15 GCs (Carretta+, 2009)J/A+A/520/A95 : Abundances of red giants in M54 & Sgr dSph (Carretta+, 2010)J/A+A/533/A69 : Spectroscopy of 124 RGB stars in NGC 1851 (Carretta+, 2011)J/A+A/534/A9 : Synthetic spectra of galactic GCs (Sbordone+, 2011)J/AJ/141/175 : Abundances in M15 RGB/RHB stars (Sobeck+, 2011)J/A+A/540/A27 : Spectroscopy in Galactic globular clusters (Saviane+, 2012)J/MNRAS/434/1681 : Extremely metal-poor stars CaII triplet (Carrera+, 2013)J/ApJ/778/149 : Abundances for 3 stars in Sgr dSph (McWilliam+, 2013)J/A+A/562/A71 : Abundances of solar neighbourhood dwarfs (Bensby+, 2014)J/ApJ/787/10 : Solar s-process contribution with GCE model (Bisterzo+, 2014)J/A+A/572/A108 : 47 Tuc red giants chemical composition (Thygesen+, 2014)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/587/A124 : Metal-poor stars towards the Galactic bulge (Koch+, 2016)J/A+A/589/A115 : Na and Al abundances of 1303 stars (Smiljanic+, 2016)J/ApJ/835/152 : HST FGS-1r plx for 8 metal-poor stars (Chaboyer+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/846/23https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/846/23http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/846/23https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/846/23https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/846/23http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/846/23GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/846/23/rgbstars (Magellan and SALT observations of NGC 6681 red giant branch stars (RGBs) and comparison of photometric and spectroscopic stellar atmosphere parameters (tables 1 and 3))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/846/23/rgbstars?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/846/23/rgbstars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/846/23/rgbstars?GETtext/xml+votable180.050000true280.8066-32.3080.0055555555555555566/478683.322582951404819e-19 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/846/23?format=asciiOpticaldefaultJ/ApJ/846/23/table2Line list for abundance analysis without hyperfine splitting (HFS) linesIon[8/63.1] Ion identifier (G1)phys.atmol.ionStagefloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[4399.7/7797.6] Wavelength of spectral line (1)0.1nmem.wl;spect.linefloatEP[0/5.9] Excitation PotentialeVphys.atmol.excitationfloatlog(gf)[-10.3/0.6] Oscillator strengthphys.atmol.oscStrengthfloatRefReference for line (2)meta.ref;pos.framecharEW4025S[3.7/183.1]? EW of lines in 4025 (1)0.1nmspect.line.eqWidthfloatnullableEW7247M[1.2/167]? EW of lines in 7247 (1)0.1nmspect.line.eqWidthfloatnullableEW8125M[1.3/150.3]? EW of lines in 8125 (1)0.1nmspect.line.eqWidthfloatnullableEW10683S[3.8/240.8]? EW of lines in 10683 (1)0.1nmspect.line.eqWidthfloatnullableEW11719S[4.4/287.4]? EW of lines in 11719 (1)0.1nmspect.line.eqWidthfloatnullableEW12591M[1.3/218.6]? EW of lines in 12591 from Magellan (1)0.1nmspect.line.eqWidthfloatnullableEW12591S[2.6/217.4]? EW of lines in 12591 from SALT (1)0.1nmspect.line.eqWidthfloatnullableEW12720M[1.8/188.5]? EW of lines in 12720 (1)0.1nmspect.line.eqWidthfloatnullableEW30380S[3/222.6]? EW of lines in 30380 (1)0.1nmspect.line.eqWidthfloatnullableEW30847M[2/159.2]? EW of lines on 30847 (1)0.1nmspect.line.eqWidthfloatnullableJ/ApJ/846/23/table4HFS-elements line listrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[4754/7417.5] Wavelength of spectral line in units of Angstroms0.1nmem.wl;spect.linedoubleIon[21.1/63.1] Ion identifier (G1)phys.atmol.ionStagefloatEP[0/4.1] Excitation PotentialeVphys.atmol.excitationfloatlog(gf)[-5.1/0.6] Oscillator strengthphys.atmol.oscStrengthfloatJ/ApJ/846/23/rgbstarsMagellan and SALT observations of NGC 6681 red giant branch stars (RGBs) and comparison of photometric and spectroscopic stellar atmosphere parameters (tables 1 and 3)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDRGB star numbermeta.id;meta.mainintprimaryf_ID[b] Flag on ID (1)meta.codecharRAJ2000[280.7/280.9] Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-32.4/-32.2] Declination (J2000)degpos.eq.dec;meta.mainTelTelescopemeta.id;instr.telcharDateUT date of observationtime.epoch;obsnullableDate2Second date of observation if anytime.epoch;obsnullableExp[3200/14000] Exposure timestime.duration;obs.exposureintS/N[76.4/125.5] Signal to noise ratio measured from rms scatter at blaze peak near 6740{AA}pixel**-1stat.snrfloatVmag[12.7/15.2] V-band magnitude converted from HST F606Wmagphot.mag;em.opt.VfloatV-I[1.1/1.8] V-I color indexmagphot.color;em.opt.V;em.opt.IfloatHRV[209.9/220] Heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloatTeffP[3951/4676] Photometric effective temperatureKphys.temperature.effectiveintloggP[0.7/2.5] Photometric surface gravitylog(cm.s**-2)phys.gravityfloatVtP[2] Photometric microturbulent velocity {xi}km/sphys.velocfloatTeff[4150/4675] Spectroscopic effective temperatureKphys.temperature.effectiveintlogg[0.6/1.6] Spectroscopic surface gravitylog(cm.s**-2)phys.gravityfloatVt[1.6/3] Spectroscopic microturbulent velocity {xi}km/sphys.veloc;pos.parallax.spectfloatEWsDisplay the equivalent width measurements for this starmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar