J/ApJ/836/177ivo://CDS.VizieR/J/ApJ/836/177doi:10.26093/cds/vizier.18360177CDSTorres G.McGruder C.D.Siverd R.J.Rodriguez J.E.Pepper J.,Stevens D.J.Stassun K.G.Lund M.B.James D.2017-11-03T12:54:03Z2017-10-30T13:22:41ZCDS support team

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

cds-question@unistra.freclipsing-binary-starsinfrared-photometryvisible-astronomyphotometryradial-velocityWe report new spectroscopic and photometric observations of the main-sequence, detached, eccentric, double-lined eclipsing binary V541Cyg (P=15.34d, e=0.468). Using these observations together with existing measurements, we determine the component masses and radii to better than 1% precision: M_1_=2.335_-0.013_^+0.017^M_{sun}_, M_2_=2.260_-0.013_^+0.016^M_{sun}_, R_1_=1.859_-0.009_^+0.012^R_{sun}_, and R_2_=1.808_-0.013_^+0.015^R_{sun}_. The nearly identical B9.5 stars have estimated effective temperatures of 10650+/-200K and 10350+/-200K. A comparison of these properties with current stellar evolution models shows excellent agreement at an age of about 190Myr and [Fe/H]~-0.18. Both components are found to be rotating at the pseudo-synchronous rate. The system displays a slow periastron advance that is dominated by general relativity (GR), and has previously been claimed to be slower than predicted by theory. Our new measurement, dot{omega}=0.859_-0.017_^+0.042^deg/century, has an 88% contribution from GR and agrees with the expected rate within the uncertainties. We also clarify the use of the gravity darkening coefficients in the light-curve fitting Eclipsing Binary Orbit Program (EBOP), a version of which we use here.2017ApJ...836..177Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/836/177CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)I/276 : Tycho Double Star Catalogue (TDSC) (Fabricius+ 2002)J/ApJ/469/355 : Teff, B-V and BC relation (Flower, 1996)J/A+AS/131/395 : Eclipsing binaries light curves models (Claret 1998)J/AJ/124/1144 : Orbits of single-lined spectroscopic binaries (Latham, 2002)J/AcA/54/207 : Ephemerids of eclipsing binaries (Kreiner, 2004)J/A+A/424/919 : Stellar models grids. Z=0.02, M=0.8 to 125 (Claret, 2004)J/A+A/446/785 : Catalogue of eclipsing variables (Malkov+, 2006)J/AJ/137/3358 : Speckle interferometry of massive stars (Mason+, 2009)J/other/IBVS/5941 : Minima and maxima of 292 variables (Hubscher+, 2010)J/other/A+ARV/18.67 : Accurate masses and radii of normal stars (Torres+, 2010)J/MNRAS/401/257 : Early-type binaries on main sequence (Khaliullin+, 2010)J/A+A/529/A75 : Limb-darkening coefficients (Claret+, 2011)J/ApJ/742/123 : Photometry and Velocity of LSPM J1112+7626 (Irwin+, 2011)J/ApJ/761/123 : KELT-1 photometry and spectroscopy follow-up (Siverd+, 2012)J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013)J/AN/334/860 : Catalog of eclipsing variables. Version 2 (Avvakumova+, 2013)J/A+A/557/A119 : Eclipsing binary system LL Aquarii (Southworth, 2013)J/other/PASA/31.24 : Milky Way detached double-lined EB catalog (Eker+, 2014)J/ApJ/832/L18 : Gaia's DR1 parallaxes vs previous measurements (Jao+, 2016)J/ApJ/831/L6 : Eclipsing binary parallaxes with Gaia data (Stassun+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/836/177https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/836/177http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/836/177https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/836/177https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/836/177http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/836/177GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapInfraredOpticaldefaultJ/ApJ/836/177/table1Heliocentric radial velocity measurements of V541 Cyg from CfARV1[-100/62] Radial velocity, primary (1)km/sspect.dopplerVelocfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Date, 2,400,000+dtime.epochdoublee_RV1[1/3] Uncertainty in RV1km/sstat.errorfloatO-C1[-3.3/3] Orbit fit residual, primarykm/sstat.fit.residual;stat.fit.param;meta.modelledfloatRV2[-96/73] Radial velocity, secondary (1)km/sspect.dopplerVelocfloate_RV2[1/3] Uncertainty in RV2km/sstat.errorfloatO-C2[-3.5/4.7] Orbit fit residual, secondarykm/sstat.fit.residual;stat.fit.param;meta.modelledfloatPhaseOrbital phasetime.phasefloatJ/ApJ/836/177/table2KELT observations of V541 Cyg East of the meridianrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Date; HJD-2400000dtime.epochdoubleRmag[14.5/15.6] Scaled KELT broad R band magnitude (1)magphot.mag;em.opt.Rdoublee_Rmag[0.002/0.04] Uncertainty in Rmagmagstat.error;phot.mag;em.opt.RdoubleJ/ApJ/836/177/table3KELT observations of V541 Cyg West of the meridianrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Date; HJD-2400000dtime.epochdoubleRmag[14.5/15.6] Scaled KELT broad R band magnitude (1)magphot.mag;em.opt.Rdoublee_Rmag[0.002/0.04] Uncertainty in Rmagmagstat.error;phot.mag;em.opt.Rdouble