J/MNRAS/519/2451ivo://CDS.VizieR/J/MNRAS/519/2451doi:10.26093/cds/vizier/bg-g7-2ckCDSArellano Ferro A.Rojas Galindo F.C.Bustos Fierro I.H.Muneer S.,Yepez M.A.Giridhar S.2026-03-02T20:04:21Z2026-02-16T11:15:59ZCDS support team

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

cds-question@unistra.frglobular-star-clustersvariable-starsphotometryvisible-astronomyastrometrymetallicityabsolute-magnitudestellar-radiieffective-temperaturestellar-distancestellar-massesA 5-yr CCD photometric VI time series of NGC 7006 is employed to perform a detailed analysis of the known population of variable stars. In the process, we have corrected inconsistent classifications, sky coordinates and found 10 new cluster member variables. An independent reddening estimate with a value E(B-V) = 0.08 +/- 0.05 is made. Using Fourier decompositions of RR Lyrae light curves and well-established calibrations, the cluster mean metallicity and distance [Fe/H]ZW = -1.53 +/- 0.15 and 41.2 +/- 1.4 kpc are estimated based on an extended sample of cluster member RRab stars. Using the Gaia DR3 data, we performed an extensive membership analysis that leads to a clean colour-magnitude diagram, and hence to the identification of variables that are likely field stars, and to considerations on the variable distribution in the horizontal branch (HB). A double-mode RR Lyrae and three CW stars are discussed. The origin of CW stars from precursors in the blue tail of the HB with very thin (~0.06 +/- 0.01 M_{Sun}_) envelopes is argued. Our models indicate that the main-sequence predecessor of RR Lyrae stars had a mass of 0.82-0.85 M_{Sun}_ and lost about 25-35 per cent of its mass during the red giant branch events before settling in the HB some 12-13.5 Gyr later.2023MNRAS.519.2451Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/519/2451CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/511/1285 : M14 (NGC 6402). Variable stars VI light curvesJ/MNRAS/499/4026 : NGC 6254 variable stars VI light curvesJ/MNRAS/488/3024 : Globular clusters members with Gaia DR2J/MNRAS/452/727 : NGC 6229 variable VI light curvesJ/MNRAS/413/1275 : VrI light curves of NGC6981 variables (Bramich+, 2011)J/MNRAS/402/226 : NGC 5053 variables VrI light curvesJ/MNRAS/298/525 : Stellar evolution models for Z = 0.0001 to 0.03J/A+A/312/111 : [Fe/H] from RR Lyrae light curves (Jurcsik+, 1996)J/AJ/129/267 : RR Lyrae variables in NGC 5272 (Cacciari+, 2005)J/AJ/117/286 : Photometry of variable stars in NGC 7006 (Wehlau+, 1999)J/other/ApSS/361.175 : M5 RR Lyr and HB VI light curves (Arellano Ferro+, 2016)V/150 : Updated catalog of variable stars in globular clustersII/183 : UBVRI Photometric Standards (Landolt 1992)I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)I/350 : Gaia EDR3 (Gaia Collaboration, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/519/2451https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/519/2451http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/519/2451https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/519/2451https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/519/2451http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/519/2451GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/519/2451/table3 (*Photometric, positional and membership data of variable stars in NGC 7006 in images FoV)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/519/2451/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/519/2451/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/519/2451/table3?GETtext/xml+votable180.050000true315.320041716.21863890.0055555555555555566/125311.9821045660507152e-19 3.9105737390043815e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/519/2451?format=asciiOpticaldefaultJ/MNRAS/519/2451/table2Time-series VI photometry for the variable stars observed in this workrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDStar identifier raw number as VNN (Star_ID)meta.id;meta.maincharFilter[V I] Filter band used (Filter)instr.setup;instr.filtercharHJDHeliocentic julian date epoch of mid-exposure (HJD)dtime.epochdoubleindexedStdmagStandard VI magnitude value in VI Johnson-Kron-Cousins as expressed in equation 1 and 2 of the section 2.2 respectively for V and I (m_std_)magphot.magfloatInstmagThe instrumental magnitude as measured by the 2m IAO telescope (m_ins_)magphot.mag;em.optfloate_InstmagUncertainty of the Instmag which also corresponds to the error of the standard magnitude Stdmag ({sigma}_m_)magstat.error;phot.magfloatJ/MNRAS/519/2451/table3*Photometric, positional and membership data of variable stars in NGC 7006 in images FoVSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDStar identifier raw number as VNNmeta.id;meta.maincharprimaryT4Indicates RR Lyrae in table 4meta.ref.urlcharf_IDFlag for new variable star found in this work (flagID)meta.codecharTypeThe variable type (Type)meta.code;src.varcharf_TypeFlag for Bl as RR Lyrae with Blazhko effect where their amplitudes correspond to the maximum observed (FlagType)meta.codecharVmag? The mean magnitude in V band (<V>)magphot.mag;em.opt.Vfloatnullablef_VmagFlag for values taken from CVSGC of Clement et al. 2001AJ....122.2587C, Cat. V/150 (flag<V>)meta.codecharImag? The mean magnitude in I band (<I>)magphot.mag;em.opt.IfloatnullableAV? The extinction A_V_ in V band (A_V_)magphys.absorptionfloatnullablef_AVFlag for values taken from CVSGC of Clement et al. 2001AJ....122.2587C, Cat. V/150 (flagA_V_)meta.codecharAI? The extinction A_I_ in V band (A_I_)magphys.absorptionfloatnullableP? Period computed in this study (Pd)dtime.period;meta.modelleddoublenullablePwsn? Period from variable star catalog of Wehlau et al. 1999AJ....117..286W, Cat. J/AJ/117/286 (PdWSN99)time.perioddoublenullablef_PwsnFlag for value taken from Pinto & Rosin 1973MmSAI..44..255P (flagPWSN99)meta.codecharHJD? The heliocentric julian day (HJD-2450000.0) (HJD_max_)dtime.epoch;pos.heliocentricdoublenullableRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainf_RAJ2000Flag for values taken from CVSGC of Clement et al. 2001AJ....122.2587C, Cat. V/150 (flagRAs)meta.codecharDEJ2000Declination (J2000)pos.eq.dec;meta.mainf_DEJ2000Flag for values taken from CVSGC of Clement et al. 2001AJ....122.2587C, Cat. V/150 (flagDEs)meta.codecharMemMembership status (Mem) (1)meta.code.membercharLCLight curvesmeta.ref.urlcharClement+17Display the Updated catalog of variable stars in globular clusters of Clement et al. (2017yCat.5150....0C, Cat. V/150)meta.ref.urlintnullableGaiaDR3Display I/355 GaiaDR3 datameta.ref.urlcharJ/MNRAS/519/2451/table4Fourier coefficients of the V light curves of RRab and RRc stars in NGC 7006TypeThe variable type RRab with 52 sources and RRc with 5 sources in our sample (Type)meta.code;src.varcharA0The Vmag intensity weighted mean that is the best estimation of mean magnitude of the V light curve (A_0_)magphot.mag;em.opt.Vfloate_A0Error of A0 (errA0)magstat.errorfloate_A1Error of A1 (errA1)magstat.errorfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDStar identifier raw number as VNNmeta.id;meta.maincharT5Link to table5.datmeta.ref.urlcharA1The first Fourier coefficient of the V light curves (A_1_)magstat.fit.param;meta.modelled;arithfloatA2The second Fourier coefficient of the V light curves (A_2_)magstat.fit.param;meta.modelled;arithfloate_A2Error of A2 (errA2)magstat.errorfloatA3The third Fourier coefficient of the V light curves (A_3_)magstat.fit.param;meta.modelled;arithfloate_A3Error of A3 (errA3)magstat.errorfloatA4The fourth Fourier coefficient of the V light curves (A_4_)magstat.fit.param;meta.modelled;arithfloate_A4Error of A4 (errA4)magstat.errorfloatphi21Fourier phase parameter {phi}_21_ defined with {phi}_ij_ = j{phi}_i_ - i{phi}_j_ ({phi}_21_)stat.fit.param;meta.modelled;arithfloate_phi21Error of phi21 (err{phi}_21_)stat.errorfloatphi31Fourier phase parameter {phi}_31_ defined with {phi}_ij_ = j{phi}_i_ - i{phi}_j_ ({phi}_31_)stat.fit.param;meta.modelled;arithfloate_phi31Error of phi21 (err{phi}_31_)stat.errorfloatphi41Fourier phase parameter {phi}_41_ defined with {phi}_ij_ = j{phi}_i_ - i{phi}_j_ ({phi}_41_)stat.fit.param;meta.modelled;arithfloate_phi41Error of phi41 (err{phi}_41_)stat.errorfloatDm? Deviation parameter D_m_ value (Dm)stat.fit.param;meta.modelled;arithfloatnullableJ/MNRAS/519/2451/table5*Physical parameters of RR Lyrae stars computed with Fourier and calibrations to correlaterecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDStar identifier raw number as VNNmeta.id;meta.maincharTypeThe variable type RRab with 39 sources and RRc with 5 sources in our sample (Type)meta.code;src.varchar[Fe/H]ZW? The iron abundance value in the scale of Zinn & West 1984ApJS...55...45Z ([Fe/H]_ZW_)log(Sun)phys.abund.Fefloatnullablee_RError of R (errR)solRadstat.errorfloate_[Fe/H]ZW? Error of [Fe/H]ZW (err[Fe/H]_ZW_)log(Sun)stat.error;phys.abund.Fefloatnullable[Fe/H]UVES? The [Fe/H]ZW transformation as eq. 4 of sect. 5.1 with UVES scale of Carretta et al. 2009A&A...508..695C ([Fe/H]_UVES_)instr.scalefloatnullablee_[Fe/H]UVES? Error of [Fe/H]UVES (err[Fe/H]_UVES_)stat.error;phys.abund.Fefloatnullable[Fe/H]Nem? The value given by the calibration of Nemec et al. (2013ApJ...773..181N) scale ([Fe/H]_Nem_)log(Sun)instr.scale;src.calib;obs.calibfloatnullablee_[Fe/H]Nem? Error of [Fe/H]Nem (err[Fe/H]_Nem_)log(Sun)stat.error;phys.abund.FefloatnullableVMag? The absolute magnitude in V band (M_V_)magphys.magAbs;em.opt.Vfloatnullablee_VMag? Error of VMag (errM_V_)magstat.error;phot.magfloatnullablelogTeffDerived effective temperature using Fourier decomposition parameters (LogT_eff_)log(K)phys.temperature.effectivefloatlogLDerived luminosity using Fourier decomposition parameters (LogL/L_{Sun}_)log(Sun)phys.luminosityfloate_logLError of logL (errLogL/L_{Sun}_)log(Sun)stat.errorfloatDComputed stellar distance using Fourier decomposition parameters (D)kpcpos.distance;meta.modelledfloate_DError of D (errD)kpcstat.errorfloatMComputed mass using Fourier decomposition parameters (M/M_{Sun}_)solMassphys.mass;meta.modelledfloate_MError of M (errM)solMassstat.errorfloatRComputed radius using Fourier decomposition parameters (R/R_{Sun}_)solRadphys.size.radius;meta.modelledfloatf_IDThese variables are not included in the calculation of [Fe/H] since their Dm parameter is larger than 5.0 (flagID)meta.codechar