J/AJ/169/340ivo://CDS.VizieR/J/AJ/169/340CDSGies D.R.Shepard K.A.Kar A.Richardson N.D.2026-03-20T12:31:55Z2026-03-20T13:19:41ZCDS support team

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

cds-question@unistra.freclipsing-binary-starsmultiple-starsphotometryvisible-astronomyThe unusal light curve of the massive eclipsing binary W Ser was recently observed with high S/N and fast cadence by the NASA TESS mission. The TESS light curve records two eclipses and relatively fast variations outside of the eclipses. The eclipse timings verify the period increase of the binary, and the period derivative implies a mass transfer rate in excess of 1e-5M_{sun}_/yr. The light curve shows a fading trend from just after an eclipse until the start of the next eclipse. The brightest flux source in the system is the accretion torus surrounding the mass gainer star, and we argue that these orbital-phase related fadings are the result of the injection of cooler gas from the mass donor entering the outskirts of the accretion torus. There are cyclic variations in the out-of-eclipse sections of the light curve that vary on a 2.8day timescale. This equals the orbital period for gas in the outer regions of the accretion torus, so the photometric variations are probably the result of transitory, overdense regions that form at the rim of the accretion torus.2025AJ....169..340Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/169/340CatalogResearchIsServedByTAP VizieR generic servicerelated-toI/357 : Gaia DR3 Part 3. Non-single stars (Gaia Collaboration, 2022)J/A+A/487/1129 : Evolutionary models of binaries (Van Rensbergen+, 2008)J/A+A/618/A112 : {beta} Lyr light curves (Mourard+, 2018)http://archive.stsci.edu/doi/resolve/resolve.html?doi=10.17909/tdkw-f793 : MASThttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/169/340https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/169/340http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/169/340https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/169/340https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/169/340http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/169/340GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/169/340/fig4Photoelectric measurements taken in 1956 by A. Fresa (1957AJ.....62..362F); Data behind Figure 4recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJD[638.4/772.3] Observation date; Heliocentric Julian Date - 2,435,000ddtime.epochfloatdmag[-0.88/0.47] Magnitude differencemagphot.mag;arith.difffloat