J/PASP/121/104ivo://CDS.VizieR/J/PASP/121/104doi:10.26093/cds/vizier.61210104CDSLee J.W.Kim S.-L.Lee C.-U.Kim H.-I.Park J.-H.Park S.-R.Koch R.H.2025-09-09T14:13:27Z2009-06-03T11:27:02ZCDS support team

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

cds-question@unistra.frmultiple-starsccd-photometryinfrared-photometryvisible-astronomybroad-band-photometryNew multiband CCD photometry is presented for the eclipsing binary GW Gem; the RI light curves are the first ever compiled. Four new minimum timings have been determined. Our analysis of eclipse timings observed during the past 79 years indicates a continuous period increase at a fractional rate of +(1.2+/-0.1)x10^10^, in excellent agreement with the value +1.1x10^-10^ calculated from the Wilson-Devinney binary code. The new light curves display an inverse O'Connell effect increasing toward longer wavelengths. Hot- and cool-spot models are developed to describe these variations but we prefer a cool spot on the secondary star. Our light-curve synthesis reveals that GW Gem is in a semidetached, but near-contact, configuration. It appears to consist of a near-main-sequence primary star with a spectral type of about A7 and an evolved early K-type secondary star that completely fills its inner Roche lobe. Mass transfer from the secondary to the primary component is responsible for the observed secular period change.2009PASP..121..104Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/PASP/121/104CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/PASP/121/104https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/PASP/121/104http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/PASP/121/104https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/PASP/121/104https://vizier.iucaa.in/viz-bin/votable?-source=J/PASP/121/104http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/PASP/121/104GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/PASP/121/104/table1CCD Photometric Observations of GW GemrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDB? Heliocentric Julian date for B banddtime.epochdoublenullableDBmag? Differential B magnitude, Var - Comp (1)magphot.mag;em.opt.B;arith.difffloatnullableHJDV? Heliocentric Julian date for V banddtime.epochdoublenullableDVmag? Differential V magnitude, Var - Comp (1)magphot.mag;em.opt.V;arith.difffloatnullableHJDRHeliocentric Julian date for R banddtime.epochdoubleDRmagDifferential R magnitude, Var - Comp (1)magphot.mag;em.opt.R;arith.difffloatHJDI? Heliocentric Julian date for I banddtime.epochdoublenullableDImag? Differential I magnitude, Var - Comp (1)magphot.mag;em.opt.I;arith.difffloatnullable