Journal Article

Absolute dimensions and apsidal motion of the eccentric binary V731 Cephei

V. Bakış, M. Zejda, İ. Bulut, M. Wolf, S. Bilir, H. Bakış, O. Demircan, J. W. Lee, M. Šlechta and B. Kučerová

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 390, issue 1, pages 399-407
Published in print October 2008 | ISSN: 0035-8711
Published online October 2008 | e-ISSN: 1365-2966 | DOI:
Absolute dimensions and apsidal motion of the eccentric binary V731 Cephei

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A detailed analysis of new and existing photometric, spectroscopic and spatial distribution data of the eccentric binary V731 Cep was performed. Spectroscopic orbital elements of the system were obtained by means of cross-correlation technique. According to the solution of radial velocities with UBVRc and Ic light curves, V731 Cep consists of two main-sequence stars with masses M1= 2.577 (0.098) M, M2= 2.017 (0.084) M, radii R1= 1.823 (0.030) R, R2= 1.717 (0.025) R and temperatures Teff1= 10 700 (200) K, Teff2= 9265 (220) K separated from each other by a= 23.27 (0.29) R in an orbit with inclination of 88°.70 (0.03). Analysis of the O–C residuals yielded a rather long apsidal motion period of U= 10 000 (2500) yr compared to the observational history of the system. The relativistic contribution to the observed rates of apsidal motion for V731 Cep is significant (76 per cent). The combination of the absolute dimensions and the apsidal motion properties of the system yielded consistent observed internal structure parameter compared to the theory . Evolutionary investigation of the binary by two methods (Bayesian and evolutionary tracks) shows that the system is t= 133(26) Myr old and has a metallicity of [M/H]=−0.04(0.02) dex. The similarities in the spatial distribution and evolutionary properties of V731 Cep with the nearby open cluster NGC 7762 suggest that V731 Cep could have been evaporated from NGC 7762.

Keywords: binaries: eclipsing; stars: early-type; stars: evolution; stars: fundamental parameters; stars: individual: V731 Cephei

Journal Article.  5099 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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