J/ApJ/754/91ivo://CDS.VizieR/J/ApJ/754/91doi:10.26093/cds/vizier.17540091CDSLovisi L.Mucciarelli A.Lanzoni B.Ferraro F.R.Gratton R.,Dalessandro E.Contreras Ramos R.2021-08-04T12:55:56Z2014-04-03T15:26:00ZCDS support team

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

cds-question@unistra.frglobular-star-clusterschemical-abundancesradial-velocitystellar-massesinfrared-photometryvisible-astronomyphotometryWe used three sets of high-resolution spectra acquired with the multifiber facility FLAMES at the Very Large Telescope of the European Southern Observatory to investigate the chemical and kinematical properties of a sample of 42 horizontal branch (HB) stars, 18 blue straggler stars (BSSs), and 86 main-sequence (MS) turnoff (TO) and sub-giant branch stars in the nearby globular cluster NGC 6397. We measured rotational velocities and Fe, O, and Mg abundances. All of the unevolved stars in our sample have low rotational velocites (vsin i<10km/s), while the HB stars and BSSs show a broad distribution, with values ranging from 0 to ~70km/s. For HB stars with T<10500K there is a clear temperature-oxygen anticorrelation that can be understood if the star position along the HB is mainly determined by the He content. The hottest BSSs and HB stars (with temperatures T>8200K and T>10500K, respectively) also show significant deviations in their iron abundance with respect to the cluster metallicity (as traced by the unevolved stars, [Fe/H]=-2.12). While similar chemical patterns have already been observed in other hot HB stars, this is the first evidence ever collected for BSSs. We interpret these abundance anomalies as due to the metal radiative levitation, occurring in stars with shallow or no convective envelopes.2012ApJ...754...91Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/754/91CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/hst : HST Archived Exposures Catalog (STScI, 2007)J/A+A/540/A27 : Spectroscopy in Galactic globular clusters (Saviane+, 2012)J/A+A/503/545 : Equivalent widths of Li, Na, Fe, Ca in NGC 6397 (Lind+, 2009)J/A+A/490/777 : Abundances of Population II stars in NGC 6397 (Lind+, 2008)J/A+A/483/183 : Catalogue of Blue Stragglers (Moretti+, 2008)J/AJ/135/2141 : F814W+F606W photometry of NGC 6397 faint stars (Richer+, 2008)J/A+A/425/509 : VI photometry of NGC 6397 (Andreuzzi+, 2004)J/A+A/287/769 : UV photometry of NGC 6397 (Burgarella+ 1994)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/754/91https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/754/91http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/754/91https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/754/91https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/754/91http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/754/91GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/754/91/samples (Coordinates, magnitudes, atmospherical parameters,masses, radial and rotational velocities, Fe, Mg, and O abundances of the BS (blue straggler star), HB (horizontal branch) or TO (main-sequence turnoff) samples (tables 2, 3 and 4))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/754/91/samples?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/754/91/samples?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/754/91/samples?GETtext/xml+votable180.050000true264.9180785-53.51536820.0055555555555555566/42076https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/754/91?format=asciiOpticalInfrareddefaultJ/ApJ/754/91/samplesCoordinates, magnitudes, atmospherical parameters,masses, radial and rotational velocities, Fe, Mg, and O abundances of the BS (blue straggler star), HB (horizontal branch) or TO (main-sequence turnoff) samples (tables 2, 3 and 4)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDIdentifier from the FLAMES 081.D-0356(A) runmeta.id;meta.mainintTypmeta.code.classcharRAJ2000[264.8/265.5] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-53.81/-53.44] Declination (J2000)degpos.eq.dec;meta.mainVmag[13/16.4] The V band magnitudemagphot.mag;em.opt.VfloatImag[12.6/15.8] The I band magnitudemagphot.mag;em.opt.IfloatTeff[5433/13183] Effective temperatureKphys.temperature.effectiveintlog(g)[3.2/4.7] Log of the surface gravitylog(cm.s**-2)phys.gravityfloatM[0.6/2] Star masssolMassphys.massfloatRV[11.8/32] Radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloate_RVUncertainty in RVkm/sstat.errorfloatvsini[1/70]? Projected rotational velocitykm/sphys.veloc.rotatintnullablee_vsini? Uncertainty in vsinikm/sstat.error;phys.veloc.rotatintnullable[Fe/H][-2.5/0.1]? Metallicitylog(Sun)phys.abund.Zfloatnullablee_[Fe/H]? Uncertainty in [Fe/H]log(Sun)stat.error;phys.abund.Fefloatnullable[Mg/H]? Log of the magnesium abundancelog(Sun)phys.abundfloatnullablee_[Mg/H]? Uncertainty in [Mg/H]log(Sun)stat.error;phys.abundfloatnullable[O/H]? Log of the oxygen abundancelog(Sun)phys.abundfloatnullablee_[O/H]? Uncertainty in [O/H]log(Sun)stat.error;phys.abundfloatnullableNotesNotesmeta.notecharnullable