EDP Sciences
Free access
Volume 409, Number 3, October III 2003
Page(s) 959 - 967
Section Stellar atmospheres
DOI http://dx.doi.org/10.1051/0004-6361:20031006

A&A 409, 959-967 (2003)
DOI: 10.1051/0004-6361:20031006

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

Ö. L. Degirmenci, Ö. Gülmen, C. Sezer, C. Ibanoglu and Ö. Çakirli

Ege University Observatory, 35100 Bornova, Izmir, Turkey
(Received 8 November 2003 / Accepted 24 June 2003)

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, mv =8.5, P=2.347 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 ( $q\sim0.75$) is in good agreement with the spectroscopic value given by Popper (1968). The masses we obtained are $1.80\pm0.10~M_{\odot}$ and  $1.35\pm0.08~M_{\odot}$ and the radii are $1.60\pm0.03~R_{\odot}$ and  $1.42\pm0.03~R_{\odot}$ 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 $_{\rm e}$ - 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  $6.4\times10^8$ yrs for the system.

Key words: stars: individual: V477 Cygni -- stars: binaries: eclipsing -- stars: fundamental parameters

Offprint request: Ö. L. Degirmenci, omerd@astronomy.sci.ege.edu.tr

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