J/AJ/148/90ivo://CDS.VizieR/J/AJ/148/90doi:10.26093/cds/vizier.51480090CDSYang Y.-G.Yang Y.Dai H.-F.Yin X.-G.2017-06-19T07:57:26Z2014-12-09T07:25:30ZCDS support team

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

cds-question@unistra.freclipsing-binary-starsinfrared-photometryvisible-astronomybroad-band-photometryWW Gem is a B-type eclipsing binary with a period of 1.2378days. The CCD photometry of this binary was performed in 2013 December using the 85cm telescope at the Xinglong Stations of the National Astronomical Observatories of China. Using the updated W-D program, the photometric model was deduced from the VRI light curves. The results imply that WW Gem is a near-contact eclipsing binary whose primary component almost fills its Roche lobe. The photometric mass ratio is q_ph_=0.48(+/-0.05). All collected times of minimum light, including two new ones, were used for the period studies. The orbital period changes of WW Gem could be described by an upward parabola, possibly overlaid by a light-time orbit with a period of P_mod_=7.41(+/-0.04)yr and a semi-amplitude of A=0.0079days(+/-0.0005days), respectively. This kind of cyclic oscillation may be attributed to the light-travel time effect via the third body. The long-term period increases at a rate of dP/dt=+3.47(+/-0.04)x10^-8^day/yr, which may be explained by the conserved mass transfer from the less massive component to the more massive one. With mass transfer, the massive binary WW Gem may be evolving into a contact binary.2014AJ....148...90Yhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/148/90CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)J/AJ/147/145 : Algol-type binaries. VIII. DI Peg & AF Gem (Yang+, 2014)J/AJ/145/9 : BVRI light curves of V382 Cyg (Yasarsoy+, 2013)J/AJ/143/122 : VR light curves of CK Boo (Yang+, 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/148/90https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/148/90http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/148/90https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/148/90https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/148/90http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/148/90GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/AJ/148/90/table2All compiled times of minimum light of the early-type eclipsing binary WW GemrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Datedtime.epochdoubleEpochEpochtime.epochfloatMethObservational method used (vi=visual, CCD, pe=photoelectric, p=plate, pg=photographic)instr.setupcharTypeMinimum type (I or II)meta.notenullableO-C1Eclipse time residual (O-C)_1_ (1)dstat.fit.residualfloatO-C2Eclipse time residual (O-C)_2_ (2)dstat.fit.residualfloatO-C3? Eclipse time residual (O-C)_3_ (3)dstat.fit.residualfloatnullableRefReference; in refs.dat filemeta.ref;pos.frameintJ/AJ/148/90/refsReferencesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRef[1/58] Reference numbermeta.id;meta.mainintprimaryBibCodeBibliographic codemeta.bib.bibcodecharAutAuthor's namemeta.bib.authorcharComCommentsmeta.notecharJ/AJ/148/90/table1VRI photometric observations of WW Gem in 2013recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJD-V? V band Heliocentric Julian Datedtime.epochdoublenullableDVmag? Differential V band magnitudemagphot.mag;em.opt.V;arith.difffloatnullableHJD-R? R band Heliocentric Julian Datedtime.epochdoublenullableDRmag? Differential R band magnitudemagphot.mag;em.opt.R;arith.difffloatnullableHJD-I? I band Heliocentric Julian Datedtime.epochdoublenullableDImag? Differential I band magnitudemagphot.mag;em.opt.I;arith.difffloatnullable