J/ApJ/887/109ivo://CDS.VizieR/J/ApJ/887/109doi:10.26093/cds/vizier.18870109CDSTorres G.Vanderburg A.Curtis J.L.Ciardi D.Kraus A.L.Rizzuto A.C.,Ireland M.J.Lund M.B.Christiansen J.L.Beichman C.A.2022-07-05T14:15:44Z2021-06-16T11:58:14ZCDS support team

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

cds-question@unistra.freclipsing-binary-starsopen-star-clustersphotometryvisible-astronomyradial-velocityWe report our spectroscopic monitoring of the detached, grazing, and slightly eccentric 12 day double-lined eclipsing binary EPIC 219568666 in the old nearby open cluster Ruprecht 147. This is the second eclipsing system to be analyzed in this cluster, following our earlier study of EPIC 219394517. Our analysis of the radial velocities combined with the light curve from the K2 mission yields absolute masses and radii for EPIC 219568666 of M_1_=1.121+/-0.013M_{sun}_ and R_1_=1.1779+/-0.0070R_{sun}_ for the F8 primary and M_2_=0.7334+/-0.0050M_{sun}_ and R_2_=0.640+/-0.017R_{sun}_ for the faint secondary. Comparison with current stellar evolution models calculated for the known metallicity of the cluster points to a primary star that is oversized, as is often seen in active M dwarfs, but this seems rather unlikely for a star of its mass and with a low level of activity. Instead, we suspect a subtle bias in the radius ratio inferred from the photometry, despite our best efforts to avoid it, which may be related to the presence of spots on one or both stars. The radius sum for the binary, which bypasses this possible problem, indicates an age of 2.76+/-0.61Gyr, which is in good agreement with a similar estimate from the binary in our earlier study.2019ApJ...887..109Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/887/109CatalogResearchIsServedByTAP VizieR generic servicerelated-toI/259 : The Tycho-2 Catalogue (Hog+ 2000)I/322 : UCAC4 Catalogue (Zacharias+, 2012)IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)I/345 : Gaia DR2 (Gaia Collaboration, 2018)J/ApJ/469/355 : Teff, B-V and BC relation (Flower, 1996)J/AJ/124/1144 : Orbits of 171 single-lined sp. binaries (Latham, 2002)J/ApJ/640/1018 : Differential photometry of V1061 Cyg (Torres+, 2006)J/AJ/136/2158 : CV Boo V-band and radial velocity curves (Torres+, 2008)J/A+A/502/253 : V636 Cen radial velocities curves (Clausen+, 2009)J/other/A+ARV/18.67 : Accurate masses and radii of normal stars (Torres+, 2010)J/A+A/512/A54 : Teff and Fbol from Infrared Flux Method (Casagrande+, 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/AJ/145/134 : Radial velocities of 108 stars in Ruprecht 147 (Curtis+, 2013)J/MNRAS/454/2863 : Teff against colours calibrations (Huang+, 2015)J/ApJS/222/14 : Planetary cand. from 1st yr K2 mission (Vanderburg+, 2016)J/AJ/152/8 : Stellar multiplicity on planetary systems I. (Kraus+, 2016)J/AJ/153/71 : Kepler follow-up observation prog. I. Imaging (Furlan+, 2017)J/AJ/155/114 : HAT-TR-318-007: a double-lined M dwarf binary (Hartman+, 2018)J/A+A/618/A93 : Gaia DR2 open clusters in the Milky Way (Cantat-Gaudin+, 2018)J/A+A/619/A176 : Chemical composition of Ruprecht 147 (Bragaglia+, 2018)J/A+A/625/A115 : Ruprecht 147 DANCe. I. (Olivares+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/887/109https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/887/109http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/887/109https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/887/109https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/887/109http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/887/109GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/887/109/table1Detrended K2 photometry of EPIC 219568666recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJD[57301.48/57382.81] Heliocentric Julian Date; HJD-2400000dtime.epochdoubleFlux[0.89/1.01] Detrended (Residual) fluxphot.flux;arith.ratiodoubleJ/ApJ/887/109/table3Heliocentric radial-velocity measurements of EPIC 219568666recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJD[57528.9/58294.83] Heliocentric Julian Date; HJD-2400000dtime.epochdoubleHRV1[-7.2/82] Heliocentric Radial Velocity, component 1km/sspect.dopplerVeloc;pos.heliocentricfloate_HRV1[0.1/0.25] Uncertainty in HRV1 (1)km/sstat.errorfloatHRV2[-22.3/117.3] Heliocentric Radial Velocity, component 2km/sspect.dopplerVeloc;pos.heliocentricfloate_HRV2[0.9/2.4] Uncertainty in HRV2 (1)km/sstat.errorfloatPhase[0.043/0.97] Orbital Phase (2)time.phasefloat