J/A+A/693/A136ivo://CDS.VizieR/J/A+A/693/A136doi:10.26093/cds/vizier.36930136CDSMoehler S.2025-03-03T20:01:09Z2025-01-17T08:37:28ZCDS support team

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

cds-question@unistra.frglobular-star-clustershorizontal-branch-starschemical-abundancesThe metal-rich ([M/H]=-0.48) bulge globular cluster NGC 6388 displays a blue horizontal branch (HB). Helium enrichment, which is correlated with changes seen among other light elements, might explain this feature. Conversely, the hot HB stars in the metal-poor globular clusters NGC 6397 and NGC 6752 display high abundances of heavy elements caused by radiative levitation. I want to determine the abundances of cool blue HB stars in NGC 6388 to verify whether they are helium-enriched. To exclude the effects of radiative levitation for NGC 6388 and to investigate the abundance changes caused by radiative levitation, I analysed the blue HB stars in NGC 6397 and NGC 6752. I obtained high-resolution spectra for all three clusters. I then determined the effective temperatures and surface gravities from UV-optical photometry (NGC 6388) and the spectra (NGC 6397, NGC 6752) together with local thermodynamic equilibrium (LTE) model spectra. The results were used together with equivalent widths by the GALA program, which provides consistent atmospheric parameters and abundances. For NGC 6397 and NGC 6752, only moderately hot HB stars were suitable for analysis with GALA. When including the literature data, a large scatter is seen at the onset of radiative levitation, followed by increasing abundances up to about 13500K (Si, Fe), then turning to a plateau (Si) and a forking (Fe) for higher temperatures. In NGC 6388, the star 4113 shows variations in radial velocity, which may indicate binarity. For the remaining three blue HB stars, the metal abundances are consistent with the products of hot hydrogen burning. The data were too noisy to allow for the helium abundances to be measured. The presence of hot hydrogen burning products in the blue HB stars in NGC 6388 could indicate helium enrichment. The abundance variations with temperature in moderately hot HB stars in NGC 6397 and NGC 6752 suggest an influence of parameters beyond rotation and effective temperature.2025A&A...693A.136Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/693/A136CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/693/A136https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/693/A136http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/693/A136https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/693/A136https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/693/A136http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/693/A136GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/693/A136/stars (List of all observed stars with coordinates from Gaia)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/693/A136/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/693/A136/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/693/A136/stars?GETtext/xml+votable180.050000true264.10239583-44.720911110.0055555555555555566/42076 42314 47125 47168https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/693/A136?format=asciidefaultJ/A+A/693/A136/starsList of all observed stars with coordinates from GaiarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterGlobular cluster namemeta.id.parentcharStarStar namemeta.id;meta.maincharRAJ2000Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainRunIdIdentification of observing runmeta.id;obschar69D0231BName of the column with fluxes in the FITS tables NGC6388_69D0231B_BLUE_flux.fits (329.43430nm-451.8527nm), NGC6388_69D0231B_REDL_flux.fits (461.84839nm-558.80300nm) and NGC6388_69D0231B_REDU_flux.fits (568.81700nm-661.27090nm)meta.id;phot.fluxchar69D0220BName of the column with fluxes in the FITS tables NGC6397_69D0220B_BLUE_flux.fits (329.49800nm-452.06592nm), NGC6397_69D0220B_REDL_flux.fits (461.99531-559.01172nm) and NGC6397_69D0220B_REDU_flux.fits (568.99438nm-665.00591nm)meta.id;phot.fluxchar65L0233AName of the column with fluxes in the FITS table NGC6752_65L0233A_BLUE_flux.fits (377.05330nm-498.08198nm)meta.id;phot.fluxcharSimbadNameSimbad column added by the CDSmeta.idcharnullablespblueShow the blue (329-454nm) spectrummeta.ref.urlchar69D0220AName of the column with fluxes in the FITS tables NGC6752_69D0220A_BLUE_flux.fits (329.51750nm-452.05420nm), NGC6752_69D0220A_REDL_flux.fits (462.02388nm-559.06499nm) and NGC6752_69D0220A_REDU_flux.fits (569.02949nm-663.07930nm)meta.id;phot.fluxcharspredlShow the red (460-559nm) spectrummeta.ref.urlcharspreduShow the red (568-664nm) spectrummeta.ref.urlcharFileBLUEName of the fits file BLUE in subdirectory spmeta.id;meta.fitscharFileREDLName of the fits file REDL in subdirectory spmeta.id;meta.fitscharFileREDUName of the fits file REDU in subdirectory spmeta.id;meta.fitscharRankColumn number in the fits file for the corresponding fluxmeta.idintJ/A+A/693/A136/ngc6388dEquivalent widths and line parameters for the stars in NGC6388loggamStarklogarithm of the Stark damping constantphys.atmol.dampingfloatloggamVdWlogarithm of the Van der Waals damping constantphys.atmol.damping;arith.zpfloatVelParam[0] velocity parameter alpha (always 0)phys.velocfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar namemeta.id;meta.maincharlambdaWavelength in {AA}0.1nmem.wldoubleEWlambdaEquivalent width in m{AA}0.1pmspect.line.eqWidthfloate_EWlambdaError of equivalent width in m{AA}0.1pmstat.errorfloatIonCodeCode of the ion (atomic_number.ionization_level)meta.code;phys.atmol.ionStagecharloggflogarithm of the oscillator strengthphys.atmol.oscStrengthfloatchiExcitation potentialeVphys.atmol.excitationfloatloggamRadlogarithm of the radiative damping constantphys.atmol.dampingfloatJ/A+A/693/A136/ngc6397dEquivalent widths and line parameters for the stars in NGC6397recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar namemeta.id;meta.maincharlambdaWavelength in {AA}0.1nmem.wldoubleEWlambdaEquivalent width in m{AA}0.1pmspect.line.eqWidthfloate_EWlambdaError of equivalent width in m{AA}0.1pmstat.errorfloatIonCodeCode of the ion (atomic_number.ionization_level)phys.atmol.ionStagecharloggflogarithm of the oscillator strengthphys.atmol.oscStrengthfloatchiExcitation potentialeVphys.atmol.excitationfloatloggamRadlogarithm of the radiative damping constantphys.atmol.dampingfloatloggamStarklogarithm of the Stark damping constantphys.atmol.dampingfloatloggamVdWlogarithm of the Van der Waals damping constantphys.atmol.damping;arith.zpfloatVelParam[0] velocity parameter alpha (always 0)phys.velocfloatJ/A+A/693/A136/ngc6752lEquivalent widths and line parameters for the stars in NGC6752 observed in 2000StarStar namemeta.id;meta.maincharlambdaWavelength in {AA}0.1nmem.wldoubleEWlambdaEquivalent width in m{AA}0.1pmspect.line.eqWidthfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordinte_EWlambdaError of equivalent width in m{AA}0.1pmstat.errorfloatIonCodeCode of the ion (atomic_number.ionization_level)phys.atmol.ionStagecharloggflogarithm of the oscillator strengthphys.atmol.oscStrengthfloatchiExcitation potentialeVphys.atmol.excitationfloatloggamRadlogarithm of the radiative damping constantphys.atmol.dampingfloatloggamStarklogarithm of the Stark damping constantphys.atmol.dampingfloatloggamVdWlogarithm of the Van der Waals damping constantphys.atmol.damping;arith.zpfloatVelParam[0] velocity parameter alpha (always 0)phys.velocfloatJ/A+A/693/A136/ngc6752dEquivalent widths and line parameters for the stars in NGC6752 observed in 2002recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar namemeta.id;meta.maincharlambdaWavelength in {AA}0.1nmem.wldoubleEWlambdaEquivalent width in m{AA}0.1pmspect.line.eqWidthfloate_EWlambdaError of equivalent width in m{AA}0.1pmstat.errorfloatIonCodeCode of the ion (atomic_number.ionization_level)phys.atmol.ionStagecharloggflogarithm of the oscillator strengthphys.atmol.oscStrengthfloatchiExcitation potentialeVphys.atmol.excitationfloatloggamRadlogarithm of the radiative damping constantphys.atmol.dampingfloatloggamStarklogarithm of the Stark damping constantphys.atmol.dampingfloatloggamVdWlogarithm of the Van der Waals damping constantphys.atmol.damping;arith.zpfloatVelParam[0] velocity parameter alpha (always 0)phys.velocfloat