J/ApJ/926/99ivo://CDS.VizieR/J/ApJ/926/99doi:10.26093/cds/vizier/ba-wy-33CDSDavis B.D.Bond H.E.Siegel M.H.Ciardullo R.2026-07-02T11:58:32Z2023-11-22T07:45:43ZCDS support team

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

cds-question@unistra.frglobular-star-clustersgiant-starshorizontal-branch-starsinfrared-photometryvisible-astronomybroad-band-photometryproper-motionsabsolute-magnitudeWe have carried out a search for above-horizontal-branch (AHB) stars-objects lying above the horizontal branch (HB) and blueward of the asymptotic giant branch (AGB) in the color-magnitude diagram-in 97 Galactic and seven Magellanic Cloud globular clusters (GCs). We selected AHB candidates based on photometry in the uBVI system, which is optimized for detection of low-surface-gravity stars with large Balmer jumps, in the color range -0.05<=(B-V)_0_<=1.0. We then used Gaia astrometry and Gaussian-mixture modeling to confirm cluster membership and remove field interlopers. Our final catalog contains 438 AHB stars, classified and interpreted in the context of post-HB evolution as follows: (1) AHB1: 280 stars fainter than M_V_=-0.8, evolving redward from the blue HB (BHB) toward the base of the AGB. (2) Post-AGB (PAGB): 13 stars brighter than M_V_~-2.75, departing from the top of the AGB and evolving rapidly blueward. (3) AHB2: 145 stars, with absolute magnitudes between those of the AHB1 and PAGB groups. This last category includes a mixture of objects leaving the extreme BHB and evolving toward the AGB, and brighter ones moving back from the AGB toward higher temperatures. Among the AHB1 stars are 59 RR Lyrae interlopers, observed by chance in our survey near maximum light. PAGB and AHB2 stars (including W Virginis Cepheids) overwhelmingly belong to GCs containing BHB stars, in accordance with predictions of post-HB evolutionary tracks. We suggest that most W Vir variables are evolving toward lower temperatures and are in their first crossings of the instability strip. Nonvariable yellow PAGB stars show promise as a Population II standard candle for distance measurement.2022ApJ...926...99Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/926/99CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/183 : UBVRI Photometric Standards (Landolt 1992)VI/65 : Evolutionary models of evolved stars (Dorman+ 1993)V/150 : Updated catalog of variable stars in globular clusters (Clement+ 2017)J/ApJ/419/596 : Pop I UV radiation models (Dorman+, 1993)J/ApJS/92/125 : Post-AGB evolution (Vassiliadis+, 1994)J/A+A/299/755 : Stellar evolution. II. Post-AGB (Bloecker+, 1995)J/AJ/112/601 : UV photometry in M79 (Hill+ 1996)J/AJ/113/1026 : Fabry-Perot Observations of M15 (Gebhardt+ 1997)J/A+A/360/472 : Proper motions in omega Centauri (van Leeuwen+, 2000)J/AJ/121/318 : BV photometry in NGC 5986 (Alves+, 2001)J/A+A/391/945 : HST phot. of 74 galactic globular clusters (Piotto+, 2002)J/A+A/423/353 : Abundances of UV-bright stars (Jasniewicz+, 2004)J/A+A/419/1123 : Equivalent widths of 3 post-AGB (Mooney+, 2004)J/ApJ/628/729 : CCD BVIc photometry of M10 stars (Pollard+, 2005)J/A+A/445/503 : Radial velocities in Omega Cen (NGC5139) (Reijns+, 2006)J/MNRAS/382/1353 : Spectral atlas of omega Cen post-MS stars (van Loon+, 2007)J/AcA/58/293 : Type-II and anomalous Cepheids in LMC (Soszynski+, 2008)J/ApJS/193/1 : UBVRIJHK color-temperature calibration (Worthey+, 2011)J/AJ/143/121 : UV data of Galactic globulars with GALEX (Schiavon+, 2012)J/AJ/146/57 : NGC 6402. I. BV photometry (Contreras Pena+, 2013)J/MNRAS/453/133 : WISE view of RV Tauri stars (Gezer+, 2015)J/AJ/151/40 : Differential BV phot. of 5 variables in M79 (Bond+, 2016)J/A+A/588/A25 : Post-AGB & CSPNe evol. models (Miller Bertolami, 2016)J/A+A/589/A1 : Extreme HB stars in {omega} Cen (Randall+, 2016)J/AJ/155/116 : Globular cluster M14. II. Variables (Contreras Pena+, 2018)J/A+A/618/A15 : Parameters of EHB stars in {omega} Cen (Latour+, 2018)J/A+A/622/A191 : 885 globular cluster giants abundances (Masseron+, 2019)J/MNRAS/499/4026 : NGC 6254 variables VI light curves (Arellano Ferro+, 2020)J/AJ/161/204 : Astrometry & phot. for 156 ZNG UV-bright stars (Bond+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/926/99https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/926/99http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/926/99https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/926/99https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/926/99http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/926/99GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/926/99/clusters (List of observed globular clusters (from Table 11); table added by CDS)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/926/99/clusters?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/926/99/clusters?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/926/99/clusters?GETtext/xml+votable180.050000true58.7604167-49.61444440.005555555555555556Cone search capability for table J/ApJ/926/99/table3 (The above-horizontal-branch (AHB) catalog; for 64 globular clusters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/926/99/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/926/99/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/926/99/table3?GETtext/xml+votable180.050000true6.68032-71.530420.005555555555555556Cone search capability for table J/ApJ/926/99/table7 (Blue stars in M14 and M10 (see Section 7.4))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/926/99/table7?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/926/99/table7?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/926/99/table7?GETtext/xml+votable180.050000true264.38821-3.247720.0055555555555555566/1133 3950 6389 9436 9666 10008 10321 10336 12405 12425 12531 12943 14489 16647 17121 19091 20001 21017 24843 25873 27237 27975 27981 27986 27992 28067 28577 28705 28741 28778 28889 28966-28967 28970 28972-28973 29187 29195 29216 29218 29231 29294 29377 29632 29636 29816 29870 30321 30378 30769 30998 31019 31043 31095 31115 31128 31398 31416-31417 31723 32790 32983 33077 33096 33098 33321 33323 33330 33635 34242 34317 36152 36971 37294 37513-37514 37550 38465 39642 39954 41011 41257 41304 41507 41522 41852 42076 42278 42314 42320 42336 42700 42761 42841 42955 42958 42990 43125 43193 43225 43227 43894 44086 44220 44427 47125 47168 47620 47777 47825 47866 47868 47971 48035 48434 48444 48698 48952https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/926/99?format=asciiOpticalInfrareddefaultJ/ApJ/926/99/clustersList of observed globular clusters (from Table 11); table added by CDSSimbadNameSimbad column added by the CDSmeta.idcharnullableNEDNED column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterGlobular cluster identifiermeta.id;meta.maincharprimaryNahbNumber of AHB stars in this cluster (link to Table 3)meta.numberintnullableNbsNumber of blue stars in this cluster (link to Table 7)meta.numberintnullableNobsNumber of observations for this cluster (link to Table 11)meta.numberintnullable_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/ApJ/926/99/table3The above-horizontal-branch (AHB) catalog; for 64 globular clusters_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.raindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decindexedClusterCluster identifier (NGC/IC number)meta.id.parentcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClNameOther cluster identifiermeta.idcharID[52/350976] Star numbermeta.id;meta.mainintRA_ICRSGaia EDR3 right Ascension (ICRS) at Epoch=2016.0degpos.eq.ra;meta.mainDE_ICRS[-84/48] Gaia EDR3 declination (ICRS) at Epoch=2016.0degpos.eq.dec;meta.mainpmRA[-8.7/10.5] Gaia EDR3 proper motion in RAmas/yrpos.pm;pos.eq.radoublepmDE[-19.6/2.7] Gaia EDR3 proper motion in DEmas/yrpos.pm;pos.eq.decdoubleDist[1.5/1386] Distance from Cluster Centerarcsecpos.angDistancefloatVMag[-3.51/0.31] Absolute V band Vega magnitude (1)magphys.magAbsfloat(B-V)0[-0.05/0.99] Intrinsic B-V colormagphot.color;em.opt.B;em.opt.Vfloat(c2)0[0.3/1.85] Intrinsic (u-B)-(B-V) colormagphot.color;em.opt;em.optfloatumag[12.33/21.15] Apparent u band magnitude; Vega+1magphot.mag;em.opt.Ufloate_umag[0.004/0.3] Uncertainty in umagmagstat.error;phot.magfloatBmag[11/19.76] Apparent B band Vega magnitudemagphot.mag;em.opt.Bfloate_Bmag[0.004/0.14] Uncertainty in Bmagmagstat.error;phot.magfloatVmag[10.67/19.33] Apparent V band Vega magnitudemagphot.mag;em.opt.Vfloate_Vmag[0.004/0.22] Uncertainty in Vmagmagstat.error;phot.magfloatImag[9.94/18.8] Apparent I band Vega magnitudemagphot.mag;em.opt.Ifloate_Imag[0.004/0.3] Uncertainty in Imagmagstat.error;phot.magfloatplx[-0.96/1.25] Gaia EDR3 parallaxmaspos.parallax.trigfloatMm[0.8/1] Membership Probabilitystat.probabilityfloatTypeAHB Classification (2)meta.code.classcharPNamePrevious Identification(s) (3)meta.idcharGaiaDisplay the Gaia EDR3 data (I/350)meta.ref.urlcharJ/ApJ/926/99/table7Blue stars in M14 and M10 (see Section 7.4)ClusterNGC numbermeta.id.parentcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClNameM14 or M10meta.idcharIDStar identifiermeta.id;meta.maincharRA_ICRS[254.2/264.5] Gaia EDR3 right ascension (ICRS) at Epoch=2016.0degpos.eq.ra;meta.mainDE_ICRS[-4.2/-3.1] Gaia EDR3 declination (ICRS) at Epoch=2016.0degpos.eq.dec;meta.main(B-V)0[-0.31/-0.046] (B-V) color indexmagphot.color;em.opt.B;em.opt.VfloatVMag[-2.1/1.5] Absolute V magnitudemagphys.magAbsfloatGaiaDisplay the Gaia EDR3 data (I/350)meta.ref.urlcharJ/ApJ/926/99/table11uBVI observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterGlobular cluster identifiermeta.id;meta.maincharTypeGlobular cluster type (1)meta.codecharClNameOther cluster identifiermeta.idcharFieldField within cluster (2)meta.id;obs.fieldcharDM[12.37/21.1] Distance modulus in V band (3)magphot.mag.distModfloatE(B-V)[0/1.24] The (B-V) color excess (3)magphot.color.excessfloatObs[1994/2001] UT Year of the observationtime.epoch;obsTelTelescope (4)meta.id;instr.telcharExp-uThe u band exposure timestime.duration;obs.exposurecharExp-BThe B band exposure timestime.duration;obs.exposurecharExp-VThe V band exposure timestime.duration;obs.exposurecharExp-IThe I band exposure timestime.duration;obs.exposurechar