Absolute parameters of the eclipsing binary V821 Cas from UBVRI light curves and radial velocities

ÇAKIRLI Ö., Ibanoglu C., Bilir S., SİPAHİ E.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol.395, no.3, pp.1649-1656, 2009 (SCI-Expanded) identifier identifier


We present UBVRI photometric measurements and spectroscopic observations of the double-lined eclipsing binary V821 Cas. The radial velocities were obtained by means of the cross-correlation technique. Simultaneous analyses of the multiband light curves and RVs give the absolute parameters for the stars as: M-1 = 2.05 +/- 0.07M(circle dot); M-2 = 1.63 +/- 0.06M(circle dot); R-1 = 2.31 +/- 0.03R(circle dot); R-2 = 1.39 +/- 0.02R(circle dot); T-eff1 = 9400 +/- 400 K and T-eff2 = 8 600 +/- 400 K. An analysis of the O-C residuals yielded an apsidal motion in the binary at a rate of omega = 0 degrees.0149 +/- 0 degrees.0023 cycle(-1), corresponding to an apsidal period of U = 118 +/- 19 yr. Subtracting the relativistic contribution, we find that log k(2obs) = -2.590 which is in agreement with the value predicted by theoretical models. Comparison with current stellar evolution models gives an age of 5.6 x 10(8) yr for the system.