J/ApJS/226/18ivo://CDS.VizieR/J/ApJS/226/18doi:10.26093/cds/vizier.22260018CDSAnderson R.I.Casertano S.Riess A.G.Melis C.Holl B.Semaan T.,Papics P.I.Blanco-Cuaresma S.Eyer L.Mowlavi N.Palaversa L.,Roelens M.2022-05-25T09:01:25Z2016-12-06T09:38:05ZCDS support team

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

cds-question@unistra.frvariable-starsradial-velocityspectroscopic-binary-starsWe investigate the radial velocity (RV) variability and spectroscopic binarity of 19 Galactic long-period (P_puls_>~10d) classical Cepheid variable stars whose trigonometric parallaxes are being measured using the Hubble Space Telescope and Gaia. Our primary objective is to constrain possible parallax error due to undetected orbital motion. Using over 1600 high-precision RVs measured between 2011 and 2016, we find no indication of orbital motion on <~5yr timescales for 18 Cepheids and determine upper limits on allowed configurations for a range of input orbital periods. The results constrain the unsigned parallax error due to orbital motion to <2% for 16 stars, and <4% for 18. We improve the orbital solution of the known binary YZ Carinae and show that the astrometric model must take into account orbital motion to avoid significant error (~+/-100{mu}arcsec). We further investigate long-timescale (P_orb_>10yr) variations in pulsation-averaged velocity v_{gamma}_ via a template fitting approach using both new and literature RVs. We discover the spectroscopic binarity of XZ Car and CD Cyg, find first tentative evidence for AQ Car, and reveal KN Cen's orbital signature. Further (mostly tentative) evidence of time-variable v_{gamma}_ is found for SS CMa, VY Car, SZ Cyg, and X Pup. We briefly discuss considerations regarding a vetting process of Galactic Leavitt law calibrators and show that light contributions by companions are insignificant for most distance scale applications.2016ApJS..226...18Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/226/18CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)J/ApJ/826/56 : HST/WFC3 obs. of Cepheids in SN Ia host gal. (Riess+, 2016)J/ApJ/824/74 : OGLE LC classification of MC Cepheids (Garcia-Varela+, 2016)J/MNRAS/455/4231 : Coralie radial velocities for l Car (Anderson+, 2016)J/AJ/150/13 : Cepheid Radial Velocities (CRaV) project (Evans+, 2015)J/A+A/579/A68 : CANDID code for interferometric observations (Gallenne+, 2015)J/ApJ/804/144 : del Cephei new spectroscopic observations (Anderson+, 2015)J/MNRAS/446/4008 : RT Aur and SZ tau UBV light curves (Evans+, 2015)J/A+A/566/L10 : Cepheid radial velocity amplitude modulations (Anderson, 2014)J/MNRAS/434/2238 : Cepheids in open clusters (Anderson+, 2013)J/A+A/553/A24 : Models for rotating stars (Georgy+, 2013)J/AJ/144/187 : Iris photom. near southern Cepheids. V. AQ Pup (Turner+, 2012)J/A+A/546/A61 : Radial velocities for XHIP catalogue (de Bruijne+, 2012)J/A+A/537/A146 : Stellar models with rotation. 0.8<M<120. (Ekstrom+, 2012)J/A+A/534/A94 : Milky Way Cepheids radial velocities (Storm+, 2011)J/ApJ/730/119 : HST/WFC3 obs. of Cepheids in SN Ia hosts (Riess+, 2011)J/ApJ/699/539 : Cepheids in SN-Ia host galaxies (Riess+, 2009)J/PAZh/35/451 : Light Curves of RS Pup (Berdnikov+, 2009)J/AcA/58/313 : LMC Cepheids in OGLE and MACHO data (Poleski+, 2008)J/AcA/58/163 : VI light curves of LMC classical Cepheids (Soszynski+, 2008)J/MNRAS/362/1167 : Radial velocities of 14 southern Cepheids (Petterson+, 2005)J/A+A/399/1167 : Hipparcos Variability-Induced Movers (Pourbaix+, 2003)J/A+AS/140/79 : Radii of 22 galactic Cepheids (Imbert, 1999)J/A+A/314/541 : Long period Cepheids (Antonello+, 1996)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/226/18https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/226/18http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/226/18https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/226/18https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/226/18http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/226/18GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/226/18/ceph (Results from RV curve modeling, upper limits and estimating photometric bias due to main sequence companions for the Cepheids (tables 1, 3, 4 and 8))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/226/18/ceph?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/226/18/ceph?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/226/18/ceph?GETtext/xml+votable180.050000true78.16333342.8316670.0055555555555555566/1431 3600 14303 14409 14625 14718 28717 29095 30222 37235 37332 37336 37340 37929 38022 39771 39908 39933 41667https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/226/18?format=asciidefaultJ/ApJS/226/18/cephResults from RV curve modeling, upper limits and estimating photometric bias due to main sequence companions for the Cepheids (tables 1, 3, 4 and 8)OtherOther name (HD or Hipparcos)meta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCepheid namemeta.id;meta.maincharprimaryNrvNumber of radial velocity measurements for this Cepheidmeta.numberintnullableSimbadSimbad column added by the CDSmeta.ref.urlcharVPVelocity Plotmeta.ref.urlcharwsini2[0/4] Projected parallax error (3)(6)(7)AUstat.error;pos.parallaxfloatnullablechisq2[27/20207] Fit {chi} square value (3)stat.fit.chi2intnullableSpTCompanion MK spectral type estimate (B2V or B4V)src.spTypecharXing[0/3] Instability crossing (8)time.crossingintnullableAge[24/82] Estimated Age (9)Myrtime.ageintnullablelogAge[7.3/8] Log Estimated Age (9)log(yr)time.agefloatnullablem1[6/10.2] Cepheid mass (10)solMassphys.massfloatnullablem2[4/7.2] Cepheid companion mass (11)solMassphys.massfloatnullabledMV[-4.6/-3.2] Magnitude contrast, V band (12)magphot.mag;arith.difffloatnullabledMI[-5.8/-3.9] Magnitude contrast, I band (12)magphot.mag;arith.difffloatnullabledMH[-7.1/-4.6] Magnitude contrast, H band (12)magphot.mag;arith.difffloatnullabledWVI[-7.7/-5] Magnitude contrast, Wesenheit index WVI=I-1.55*(V-I) (12)magphot.mag;arith.difffloatnullabledWHVI[-7.6/-4.9] Magnitude contrast, Wesenheit index WHVI=H-0.4*(V-I) (12)magphot.mag;arith.difffloatnullableNtDisplay the time-variable v{gamma} data for this Cepheidmeta.ref.urlintnullableRAJ2000Hour of Right Ascension (J2000) (1)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000) (1)pos.eq.dec;meta.mainVmag[7.5/10] Mean V band magnitude (1)magphot.mag;em.opt.VfloatNcor[0/118] Number of Observations, Coraliemeta.numberintNham[0/78] Number of Observations, Hamiltonmeta.numberintNher[0/45] Number of Observations, Hermesmeta.numberintdtObs[1/5] Total temporal baseline of new observationsyrtime.epochfloatRefReferences (see refs.dat file) (2)meta.refcharPpuls[9/69.7] Pulsation Perioddtime.perioddoubleEpochEpoch of minimal RV, BJD-2400000dtime.epochdoubleNfs[5/13] Number of harmonics used in fit Fourier seriesmeta.numberintVgam[-69.5/77.1] Systemic mean velocity ({nu}_{gamma}_)km/sphys.velocfloate_Vgam[0.03/0.6] Standard mean error on Vgamkm/sstat.errorfloatAp2p[19.2/59.6] Peak-to-peak amplitudekm/sphys.veloc;src.orbitalfloatA1[9/26.1] First harmonic amplitudekm/ssrc.var.amplitudefloatR21[0.03/0.5] Fourier amplitude ratio: 2,1src.var.amplitude;arith.ratiofloatphi21[2.9/5.3] Fourier phase ratio: 2,1stat.fit.paramfloatR31[0.01/0.3] Fourier amplitude ratio: 3,1src.var.amplitude;arith.ratiofloatphi31[1.6/7.5] Fourier phase ratio: 3,1stat.fit.paramfloatrms[0.03/0.9] Fit Fourier rmskm/sstat.fit.param;meta.modelledfloatdt[1.3/5.1] Temporal baseline of new observationsyrtime.epochfloatnullabledof[33/111] Degrees of freedom after the fitstat.fit.dof;stat.fit.param;meta.modelledintnullablePorb1[0.7/4] Derived orbital period (3)yrtime.periodfloatnullableK1[0.07/2] Orbital semi-amplitude (3)km/ssrc.var.amplitudefloatnullablee_K1[0.001/1.2] Uncertainty in K1 (3)(4)km/sstat.errorfloatnullableasini1[0.2/6.4] Projected semi-major axis (3)(7)(5)AUphys.size.smajAxisfloatnullablewsini1[0/7] Projected parallax error (3)(7)(6)AUstat.error;pos.parallaxfloatnullablechisq1[32/20618] Fit {chi} square value (3)stat.fit.chi2intnullablePorb2[0.6/2.5] Derived orbital period (3)yrtime.periodfloatnullableK2[0.1/1.2] Orbital semi-amplitude (3)km/ssrc.var.amplitudefloatnullablee_K2[0.001/0.8] Uncertainty in K1 (3)(4)km/sstat.errorfloatnullableasini2[0.2/5.8] Projected semi-major axis (3)(5)(7)AUphys.size.smajAxisfloatnullableJ/ApJS/226/18/table2RV data obtained for this programrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCepheid namemeta.id;meta.maincharBJD[55652.8/57536.9] Observation time, BJD-2400000dtime.epochdoublePhiPulsation Phase ({phi}_puls_) (1)time.phasefloatRVel[-84.7/98.4] Barycentric radial velocitykm/sphys.veloc;pos.barycenterfloate_RVel[0.005/0.2] Uncertainty in RVelkm/sstat.error;spect.dopplerVelocfloatInstInstrument used (2)instr.setupcharJ/ApJS/226/18/vgamTime-variable v{gamma} of new spectroscopic binaries (table 6) or time-dependent v{gamma} for reported binary Cepheids (table 7) based on RV template fittingNameCepheid namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTvarmeta.codecharPpuls[9.7/34.1] Pulsation Period (1)dtime.periodfloatEpoch[25787.5/57509.5] Epoch of minimal RV, BJD-2400000 (1)dtime.epochdoubledt[0.02/7.5] Timespan of the measurements ({Delta}t)yrtime.epochfloatNrv[5/98] Number of RVel measurements fittedmeta.numberintVgam[-42.4/77.2] Systemic mean velocity ({nu}_{gamma}_) (1)km/sphys.velocfloatstdmer[0.05/2.6] Standard mean error based on residual scatterkm/sstat.errorfloatl_sigVLimit flag on sigVmeta.code.errorcharsigV[0.001/20.2] Uncertainty from the fit covariance matrix ({sigma}({nu}_{gamma}_))km/sstat.errorfloatRefReferences (see refs.dat file)meta.refcharJ/ApJS/226/18/refsReferencesBibCodeBibcodemeta.bib.bibcodecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference codemeta.notecharAuthFirst author's name(s)meta.bib.authorcharCommCommentmeta.notechar