J/ApJ/868/30ivo://CDS.VizieR/J/ApJ/868/30doi:10.26093/cds/vizier.18680030CDSPilecki B.Dervisoglu A.Gieren W.Smolec R.Soszynski I.,Pietrzynski G.Thompson I.B.Taormina M.2019-11-19T06:45:24Z2019-11-18T15:17:49ZCDS support team

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

cds-question@unistra.freclipsing-binary-starsinfrared-photometryvisible-astronomyphotometryradial-velocitystellar-evolutionary-modelsWe present the analysis of a peculiar W Virginis (pWVir) type II Cepheid, OGLE-LMC-T2CEP-211 (P_puls_=9.393d), in a double-lined binary system (P_orb_=242d), which shed light on virtually unknown evolutionary status and structure of pWVir stars. The dynamical mass of the Cepheid (first ever for a type II Cepheid) is 0.64+/-0.02M_{sun}_, and the radius R=25.1+/-0.3R_{sun}_. The companion is a massive (5.67M_{sun}_) main-sequence star obscured by a disk. Such a configuration suggests a mass transfer in the system history. We found that originally the system (P_orb_^init^=12d) was composed of 3.5 and 2.8M_{sun}_ stars, with the current Cepheid being more massive. The system age is now ~200Myr, and the Cepheid is almost completely stripped of hydrogen, with helium mass of ~92% of the total mass. It finished transferring the mass 2.5Myr ago and is evolving toward lower temperatures passing through the instability strip. Comparison with observations indicates a reasonable 2.7x10^-8^M_{sun}_/yr mass loss from the Cepheid. The companion is most probably a Be main-sequence star with T=22000K and R=2.5R_{sun}_. Our results yield a good agreement with a pulsation theory model for a hydrogen-deficient pulsator, confirming the described evolutionary scenario. We detected a two-ring disk (R_disk_~116R_{sun}_) and a shell (R_shell_~9R_{sun}_) around the companion, which is probably a combination of the matter from the past mass transfer, the mass being lost by the Cepheid owing to wind and pulsations, and a decretion disk around a rapidly rotating secondary. Our study, together with observational properties of pWVir stars, suggests that the majority of them are products of a similar binary evolution interaction.2018ApJ...868...30Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/868/30CatalogResearchIsServedByTAP VizieR generic servicerelated-toVI/120 : High-resolution synthetic stellar library (Coelho+, 2005)J/A+A/454/855 : Geneva photometry of W Cru (Pavlovski+, 2006)J/AcA/58/293 : Type-II and anomalous Cepheids in LMC (Soszynski+, 2008)J/AcA/60/91 : VI light curves of SMC type II Cepheids (Soszynski+, 2010)J/MNRAS/413/223 : Magellanic clouds Cepheids JHKs photometry (Matsunaga+, 2011)J/MNRAS/436/953 : OGLE-LMC-CEP-0227 RV and VI[3.6] curves (Pilecki+, 2013)J/A+A/604/A29 : MC Type II & anomalous Cepheids PL & PR (Groenewegen+, 2017)J/AcA/68/89 : VI light curves of SMC type II Cepheids (Soszynski+, 2018)J/ApJ/854/109 : Photometry & spectroscopy follow-up of MWC 882 (Zhou+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/868/30https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/868/30http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/868/30https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/868/30https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/868/30http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/868/30GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tap2.367228618189496e-19 2.6706780932288093e-19OpticalInfrareddefaultJ/ApJ/868/30/table4Evolutionary modelsq-i[0.5/1] Mass Ratio, initialphys.mass;arith.ratiofloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintbeta[0/1] Systemic Mass Loss Fractionphys.mass;arith.ratiofloatMd-i[3.3/9.7] Mass, donor, initialsolMassphys.massfloatMa-i[2.1/5.2] Mass, accretor, initialsolMassphys.massfloatMtot[6.3/14.5] Mass, totalsolMassphys.massfloatPer-i[11.6/56.2] Orbital Period, initialdtime.periodfloatq[0.5/8] Mass Ratio, final fitphys.mass;arith.ratiofloatMd[0.7/9.7] Mass, donor, final fitsolMassphys.massfloatlogTd[3.6/4.4] log Surface Temperature, donor, final fitlog(K)phys.temperaturefloatlogLd[2.4/3.7] log Stellar Luminosity, donor, final fitlog(solLum)phys.luminosity;meta.modelledfloatlogRd[0.5/1.8] log Stellar Radius, donor, final fitlog(solLum)phys.size.radiusfloatloggd[1.4/4.1] log Surface Gravity, donor, final fitlog(cm.s**-2)phys.gravityfloatMa[2.7/5.7] Mass, accretor, final fitsolMassphys.massfloatlogTa[3.9/4.4] log Surface Temperature, accretor, final fitlog(K)phys.temperaturefloatlogLa[1.6/3.3] log Stellar Luminosity, accretor, final fitlog(solLum)phys.luminosity;meta.modelledfloatlogRa[0.2/0.6] log Stellar Radius, accretor, final fitlog(solLum)phys.size.radiusfloatlogga[4/4.6] log Surface Gravity, accretor, final fitlog(cm.s**-2)phys.gravityfloatPer[24.8/186.6] Orbital Period, final fitdtime.period;meta.modelledfloatChi2[9.8/100000] Chi-square statisticstat.fit.chi2doubleJ/ApJ/868/30/fig2V- and I-band light curves of the Cepheid OGLE-LMC-T2CEP-211 (data behind Figure 2)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJD-V? Heliocentric Julian Date; HJD-2450000dtime.epochdoublenullableVmag[16.6/17.4]? Warsaw/OGLE/LCO V-band magnitudemagphot.mag;em.opt.Vfloatnullablee_Vmag[0.004/0.02]? Uncertainty in Vmagmagstat.error;phot.mag;em.opt.VfloatnullableHJD-IcHeliocentric Julian Date; HJD-2450000dtime.epochdoubleIcmag[15.8/16.6] Warsaw/OGLE/LCO Cousins I-band magnitudemagphot.mag;em.opt.Ifloate_Icmag[0.004/0.01] Uncertainty in Imagmagstat.error;phot.mag;em.opt.IfloatJ/ApJ/868/30/fig7Orbital radial velocities of the Cepheid (data behind Figure 7)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Date; HJD-2450000dtime.epochdoubleRV1[186/300] Orbital radial velocity of the Cepheidkm/sspect.dopplerVelocfloatRV2[235/249]? Orbital radial velocity of the companionkm/sspect.dopplerVelocfloatnullable