J/AJ/152/49ivo://CDS.VizieR/J/AJ/152/49doi:10.26093/cds/vizier.51520049CDSYang Y.-G.Wu C.Van Hamme W.Hu J.-Y.Wei J.-Y.2017-06-19T07:58:08Z2016-09-13T14:20:03ZCDS support team

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

cds-question@unistra.frvariable-starseclipsing-binary-starsspectroscopic-binary-starsphotometryWe present a new UV light curve of the Algol eclipsing binary V548 Cyg obtained with the Lunar Ultraviolet Telescope. We model the UV light curve together with two previously published (B and V) light curves, primary star radial velocities, and eclipse timings in a unified multi-data-type solution and determine orbital parameters and absolute dimensions. Timing residuals hint at the presence of a third star in the system. This star is possibly the source of the third light that is needed to obtain a good fit to each of the light curves simultaneously. The light-time oscillation in the timing residuals has a period of either ~19 or ~46years. The third body orbit inclination would have to be low (23{deg} or 15{deg}, respectively) for the third star to have a mass of ~1.5M_{Sun}_, which would be expected for a main-sequence star of color B-V~0.32, as determined from the light curve solution. In an H-R diagram, the mass-gaining, primary component of V548 Cyg is located between the zero-age and terminal-age main sequence for solar composition stars, and close to the 0.4Gyr isochrone.2016AJ....152...49Yhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/152/49CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)J/AN/334/860 : Catalogue of eclipsing variables. V2 (Avvakumova+, 2013)J/other/JAVSO/39.23 : Maxima of short period pulsating stars (Samolyk+, 2011)J/other/JAVSO/38.183 : Time of minima of eclipsing binaries (Samolyk+, 2010)J/other/IBVS/5761 : Minima and maxima of 389 variables (Hubscher+, 2007)J/AcA/54/207 : Ephemerids of eclipsing binaries (Kreiner, 2004)J/A+A/417/263 : Catalogue of Algol type binary stars (Budding+, 2004)J/other/IBVS/5296 : Extrema of pulsating stars (Agerer+, 2002)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/152/49https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/152/49http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/152/49https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/152/49https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/152/49http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/152/49GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/152/49/table2Lunar Ultraviolet Telescope (LUT) light curve of V548 CygrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Date of observationdtime.epochdoubledmag[0.297/1.411] Differential LUT band magnitude (1)magphot.mag;arith.difffloat