Up-to-date UBV light and O–C curves analyses of the eclipsing binary V477 Cygni^*

Ege University Observatory, 35100 Bornova, İzmir, Turkey

Corresponding author: Ö. L. Deǧirmenci, omerd@astronomy.sci.ege.edu.tr

Received: 8 November 2003
Accepted: 24 June 2003

Abstract

New and complete UBV light curves and times of minimum are presented for the Algol–type eclipsing binary V477 Cygni (Sp. A3 V+F5 V, m_v =8.5,  days). The binary orbit of the system is highly eccentric and the system shows an apsidal motion. Using the Wilson-Devinney method, two photometric models, without (MODEL A) and with (MODEL B) third–body light contribution to the total light of the system, are obtained. Period analysis also gives some slender evidence for the unseen third-body in the system with the orbital period of about 157 years. In the MODEL A approximation the apsidal motion period is obtained to be 371 years while it is about 434 years in the MODEL B approximation. The photometric mass ratio () is in good agreement with the spectroscopic value given by Popper (1968). The masses we obtained are and  and the radii are and  for the primary and secondary components, respectively. Absolute dimensions have been compared with the models using a moderate amount of convective overshooting and mass loss given by Claret & Giménez (1991). In the log M – log R diagram both components are located above but close to the ZAMS. It is possible to say from the log T_e – log L diagram that the secondary component is just coming to the main sequence while the primary is slightly evolved from the ZAMS. The theoretical evolutionary models give an age of  yrs for the system.