2001A&A...374..638D

The present study deals with the problem of the estimation of the orbital and physical parameters for the EB-type eclipsing binary RY Sct, based on the interpretation of new photometric U B V R observations. The light curves obtained at the Maidanak Observatory during 1979-94 show a slight asymmetry around the secondary minima and a small difference in the height of the successive maxima. The light curves are analysed in the framework of the Roche computer model (Djurasevic, 1992Ap&SS.196..241D) by applying the inverse-problem method (Djurasevic, 1992Ap&SS.197...17D) based on Marquardt's (1963,J. Soc. Ind. Appl. Math. 11(2), 431) algorithm. The analysis shows that RY Sct system is in an overcontact configuration (f_over∼33%) with q=m₂/m₁=3.3 and i∼84.3°, generating total-annular eclipses. The basic parameters of the system and of the active region are estimated for all individual U, B, V and R light curves. Our results suggested a mass exchange between the components and mass loss through the outer Lagrangian point L₃. This could be taken as a possible mechanism in the formation of the circumstellar envelope of toroidal form lying in the orbital plane of the system.