J/AJ/153/231ivo://CDS.VizieR/J/AJ/153/231doi:10.26093/cds/vizier.51530231CDSSriram K.Malu S.Choi C.S.Vivekananda Rao P.2017-09-04T08:40:18Z2017-08-10T16:08:27ZCDS support team

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

cds-question@unistra.freclipsing-binary-starsinfrared-photometryvisible-astronomybroad-band-photometryWe present the multi-band photometric and spectroscopic study of an over-contact binary system, EPIC211957146. The light curves exhibit a variable O' Connell effect, confirmed from our observational data and the Kepler K2 data. The best photometric solution incorporating a dark spot over the primary component unveils that the system has a low-mass ratio (q~0.17) and a high inclination (i~85{deg}). To confirm the solution and constrain the uncertainty, Monte-Carlo simulations are performed and the results are reported. Based on the O-C diagram analysis, we see that the variable shows a period increase at the rate of dP/dt~1.06x10^-6^days/yr, which is higher than the theoretically predicted value. Presence of a third body having a period of ~16.23years is evident from the O-C diagram. No filled-in effect is observed in the H{alpha} line, while the effect is vividly present in the Na line. From the Kepler K2 data, we found that the primary and secondary minima exhibit an anti-correlated O-C variation followed by an erratic behavior. This is possibly caused by the longitudinal motion of the spot, and hence, we set a lower limit of ~40days for the spot modulation. We also observe a possibly associated photometric difference in the primary depth by comparing our light curves with Kepler K2 normalized light curves. This system has a low-mass ratio and a high fill-out factor, and, theoretically, such a physical configuration would lead to a merger.2017AJ....153..231Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/153/231CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)J/AJ/135/907 : Variables in Praesepe identified with KELT (Pepper+, 2008)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/153/231https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/153/231http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/153/231https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/153/231https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/153/231http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/153/231GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapInfraredOpticaldefaultJ/AJ/153/231/table2Observed times of minima for variable EPIC 211957146e_HJD[0.00013/0.00898] Uncertainty in HJDdstat.error;time.epochdoubleEpoch[-17388/8.5] Number of the cyclemeta.number;time.perioddoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Date (HJD-2450000)dtime.epochdoubleO-C1[-0.042/0.02] (O-C) residual (obtained from the linear ephemeris)dstat.fit.residual;stat.fit.omcdoubleO-C2[-0.036/0.032] (O-C) residual, quadratic ephemeris+LIght-travel Time Effect (LITE)dstat.fit.residual;time.epoch;stat.fit.omcdoubleRef[1/5] Reference (1)meta.ref;pos.frameintJ/AJ/153/231/figure1BVR band light curve data behind Figure 1HJD? Heliocentric Julian Datedtime.epochdoublenullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBand[BVR] Band of observation (either B, V, or R)instr.bandpass;obscharPhase[-0.285/1]? Phasetime.phasedoublenullableNFlux[0.6/1.01]? Normalized light unitsmeta.unit;phys.composition.massLightRatiodoublenullable