J/A+A/526/A136ivo://CDS.VizieR/J/A+A/526/A136doi:10.26093/cds/vizier.35260136CDSMoehler S.Dreizler S.Lanz T.Bono G.Sweigart A.V.Calamida A.,Nonino M.2017-10-09T13:34:38Z2011-08-18T09:15:55ZCDS support team

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

cds-question@unistra.frglobular-star-clustershorizontal-branch-starsradial-velocityeffective-temperatureUV observations of some massive globular clusters have revealed a significant population of stars hotter and fainter than the hot end of the horizontal branch (HB), the so-called blue hook stars. This feature might be explained either by the late hot flasher scenario where stars experience the helium flash while on the white dwarf cooling curve or by the progeny of the helium-enriched sub-population postulated to exist in some clusters. Previous spectroscopic analyses of blue hook stars in omega Cen and NGC 2808 support the late hot flasher scenario, but the stars contain much less helium than expected and the predicted C and N enrichment cannot be verified. We compare the observed effective temperatures, surface gravities, helium abundances, and carbon line strengths (where detectable) of our targets stars with the predictions of the two aforementioned scenarios.2011A&A...526A.136Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/526/A136CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/663/1021 : Log of {omega} Cen scientific images (Castellani+, 2007)J/MNRAS/399/195 : Blue & red spectra of {omega} Cen HB stars (Van Loon+, 2009)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/526/A136https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/526/A136http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/526/A136https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/526/A136https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/526/A136http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/526/A136GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/526/A136/table1 (Target coordinates, heliocentric radial velocities, and B brightness)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/526/A136/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/526/A136/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/526/A136/table1?GETtext/xml+votable180.050000true201.392917-47.4972220.0055555555555555566/43225 43227https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/526/A136?format=asciiOpticaldefaultJ/A+A/526/A136/table1Target coordinates, heliocentric radial velocities, and B brightnessrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqSequential number (<[MDL2011] NNNNNN> in Simbad)meta.recordintprimaryn_Seq[1/4]? Note on target star (1)meta.noteintnullableASimbad column added by the CDSmeta.ref.urlcharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainBmagB magnitudemagphot.mag;em.opt.BfloatHRV? Heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloatnullableSimbadSimbad column added by the CDSmeta.refcharJ/A+A/526/A136/table34Atmospheric parameters for stars with sub-solar (table3) or super-solar (table4) helium abundancesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintf_SeqSimbad column added by the CDSmeta.codecharSeqSequential numbermeta.recordintn_Seq[C] dedicated model atmosphere (1)meta.notecharchi2chi^2^ valuestat.fit.chi2floatTeffEffective temperatureKphys.temperature.effectiveinte_Teffrms uncertainty on TeffKstat.error;phys.temperature.effectiveintloggSurface gravitylog(cm.s**-2)phys.gravityfloate_loggrms uncertainty on logglog(cm.s**-2)stat.errorfloatlog(He/H)He/H number density ratiophys.density;arith.ratiofloate_log(He/H)rms uncertainty on log(He/H)stat.errorfloat