J/PASP/130/C4201ivo://CDS.VizieR/J/PASP/130/C4201doi:10.26093/cds/vizier.61313201CDSLee J.W.Park J.-H.2025-09-09T14:14:51Z2018-06-05T11:45:23ZCDS support team

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

cds-question@unistra.freclipsing-binary-starsinfrared-photometryvisible-astronomybroad-band-photometryNew CCD photometric observations of UZ Leo were obtained between 2012 February and 2013 April, and on 2017 February. Its physical properties were derived from detailed analyses of our light curves and existing radial velocities. The results indicate that this system is a totally eclipsing A-subtype overcontact binary with both a high fill-out factor of 76% and a third light source contributing 12% light in the B bandpass, 10% in V, and 7% in R. The light residuals between observations and theoretical models are satisfactorily fitted by adopting a magnetic cool spot on the more massive primary star. Including our 12 measurements, a total of 172 eclipse times were used for ephemeris computations. We found that the orbital period of UZ Leo has varied due to a periodic oscillation superposed on an upward parabolic variation. The observed period increase at a rate of +3.49x10^-7^day/yr can be plausibly explained by some combination of non-conservative mass transfer from the secondary to the primary component and angular momentum loss due to magnetic braking. The period and semi-amplitude of the oscillation are about 139 years and 0.0225 days, respectively, which is interpreted as a light-time effect due to a third component with a mass of M_3_sini_3_=0.30M_\{sun}_. Because the third lights of 7%-12% indicate that the circumbinary object is very overluminous for its mass, it would possibly match a white dwarf, rather than an M-type main sequence.2018PASP..130c4201Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/PASP/130/C4201CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/PASP/130/C4201https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/PASP/130/C4201http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/PASP/130/C4201https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/PASP/130/C4201https://vizier.iucaa.in/viz-bin/votable?-source=J/PASP/130/C4201http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/PASP/130/C4201GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/PASP/130/C4201/table1CCD photometric data of UZ Leo observed in 2012 and 2013recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJD-BB band Heliocentric Julian date of observationdtime.epochdoubleDBmagDifferential B magnitudemagphot.mag;em.opt.B;arith.difffloatHJD-V? V band Heliocentric Julian date of observationdtime.epochdoublenullableDVmag? Differential V magnitudemagphot.mag;em.opt.V;arith.difffloatnullableHJD-R? R band Heliocentric Julian date of observationdtime.epochdoublenullableDRmag? Differential R magnitudemagphot.mag;em.opt.R;arith.difffloatnullable