J/ApJ/809/129ivo://CDS.VizieR/J/ApJ/809/129doi:10.26093/cds/vizier.18090129CDSMiroshnichenko A.S.Zharikov S.V.Danford S.Manset N.Korcakova D.,Kricek R.Slechta M.Omarov C.T.Kusakin A.V.Kuratov K.S.,Grankin K.N.2017-06-01T08:52:33Z2016-01-13T07:18:15ZCDS support team

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

cds-question@unistra.frspectroscopic-binary-starsline-intensitiesbe-starsspectroscopyWe report the results of a long-term spectroscopic monitoring of the FS CMa type object MWC 728. We found that it is a binary system with a B5Ve (Teff=14000+/-1000K) primary and a G8III type (Teff~5000K) secondary. Absorption line positions of the secondary vary, with a semi-amplitude of ~20km/s and a period of 27.5 days. The system's mass function is 2.3x10^-2^M_{sun}_, and its orbital plane is ~13{deg}-15{deg} tilted from the plane of the sky. The primary's vsini~110km/s, combined with this tilt, implies that it rotates at a nearly breakup velocity. We detected strong variations of the Balmer and HeI emission-line profiles on timescales from days to years. This points to a variable stellar wind of the primary in addition to the presence of a circum-primary gaseous disk. The strength of the absorption-line spectrum, along with the optical and near infrared (IR) continuum, suggest that the primary contributes ~60% of the V-band flux, the disk contributes ~30%, and the secondary contributes ~10%. The system parameters, along with the interstellar extinction, suggest a distance of ~1kpc, that the secondary does not fill its Roche lobe, and that the companions' mass ratio is q~0.5. Overall, the observed spectral variability and the presence of a strong IR-excess are in agreement with a model of a close binary system that has undergone a non-conservative mass-transfer.2015ApJ...809..129Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/809/129CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/PASP/126/469 : PolarBase catalogue of stellar spectra (Petit+, 2014)J/A+A/537/A146 : Stellar models with rotation. 0.8<M<120 (Ekstrom+, 2012)J/A+A/537/A120 : Rotational velocities of A-type stars. IV. (Zorec+, 2012)J/MNRAS/400/518 : Velocity & proper motion of OB associations (Melnik+, 2009)J/A+A/501/297 : Effective temperatures of B Supergiants (Zorec+, 2009)J/A+A/487/1129 : Evolutionary models of binaries (Van Rensbergen+, 2008)J/A+A/479/827 : UBVR light curves of weak-line T Tauri stars (Grankin+, 2008)J/MNRAS/363/1111 : Tycho-2 stars with IR excess (Clarke+, 2005)J/A+A/440/305 : Fundamental param. of fast-rotating B stars (Fremat+, 2005)J/A+A/408/305 : Spectroscopic obs. of delta Sco (Miroshnichenko+, 2003)J/A+A/384/145 : Compiled cat. of Per OB2 star forming complex (Belikov+, 2002)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/809/129https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/809/129http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/809/129https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/809/129https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/809/129http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/809/129GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/809/129/table4Properties of the H{alpha} line in the spectra of MWC 728recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJD[3363.7/7065.6] Julian Date; JD-2450000dtime.epochdoubleIv[1.9/7.3] Blue emission peak intensity in continuum unitsspect.line.intensityfloatIr[3.5/12.5] Red emission peak intensity in continuum unitsspect.line.intensityfloatEW[14.7/62] Equivalent width; Angstroms0.1nmspect.line.eqWidthfloatPhaseOrbital phasetime.phasefloatObsObservatory identifier code (1)meta.codechar