Journal Article

Long-term photometric study of the W UMa binary star V523 Cas

X. B. Zhang and R. X. Zhang

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 347, issue 1, pages 307-315
Published in print January 2004 | ISSN: 0035-8711
Published online January 2004 | e-ISSN: 1365-2966 | DOI:
Long-term photometric study of the W UMa binary star V523 Cas

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We present a long-term photoelectric and charge-coupled device (CCD) photometric study of the short-period W UMa star V523 Cas made from 1986 to 2000. The orbital-period changes and light-curve variations of the binary system are studied. 47 new times of minima are obtained from our data. A period study covering more than 43 000 cycles based on the photoelectric and CCD photometric times of minima confirms the long-term, secular period changes of the system. It is found that the orbital period has been continuously increasing in the past three decades at a rate of dP/dt= 8.84 × 10−8 d yr−1. No cyclic period variations are found from our result. Eight V and five B completely covered light curves are formed from the observations made in eight epochs. The light curves are of W UMa type and show marked asymmetries with unequal maxima. The differences between the two maxima in each light curve appear to be cyclic over a time-scale of about 8 yr. Based on a one-spot model, the light curves are analysed with the Wilson–Devinney code. The photometric solutions reveal a W-subtype, contact configuration for V523 Cas. The photometric mass ratio is found to be 0.51, and the masses and radii for the components are deduced as 0.75 ± 0.03 M, 0.74 ± 0.04 R for the primary and 0.38 ± 0.02 M, 0.55 ± 0.02 R for the secondary, respectively. We discuss the evolutionary status of the system as well as the possible spot activity along with the mass transfer among the components.

Keywords: binaries: eclipsing; stars: individual: V523 Cas; stars: late-type

Journal Article.  4254 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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