AAVSO: American Association of Variable Star Observers

V963 Persei as a Contact Binary

Volume 49 number 2 (2021)

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Joel A. Eaton
7050 Bakerville Road, Waverly, TN 37185; eatonjoel@yahoo.com
Gary W. Steffens
Morning Star Observatory, Tucson, AZ; gwsteffens@yahoo.com
Andrew P. Odell
Northern Arizona University, Flagstaff, AZ 86011; deceased, May 10, 2019

Abstract

We have reanalyzed V963 Persei, a close binary star which R. G. Samec claimed to have components with very similar masses (q = M2 / M1 = 0.87), finding that the mass ratio is actually q ≈ 0.35. The system seems to be marginally in contact with a large temperature difference between the components, similar to a class of binaries analyzed by Kałużny. Primary eclipse is a complete transit, and the peculiarities of the light curve and, more particularly, its changes, are best explained by a cool spot on the more massive component and a hot spot on the less massive one. We classify the spectrum as F9–G1, present radial velocities for both components, and analyze the light curves for various combinations of cool and hot spots. The system overfills its Roche lobe in all our solutions, but the degree depends uncomfortably on assumptions about spottedness. The masses are M1 = 1.60 ± 0.50 and M2 = 0.54 ± 0.20 M☉. Finally, we discuss limitations on our ability to determine properties of contact binaries and the apparent absurdity of some of our results.