A Photometric Study of the Near-Contact Binary SY Boötis

Volume 52 number 2 (2024)

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Edward J. Michaels

Waffelow Creek Observatory, 10780 FM 1878, Nacogdoches, TX 75961; astroed@ejmj.net

Abstract

In this paper the first multi-band photometric observations of the eclipsing binary SY Boo are presented. The β Lyrae type light curves display continuously changing light, except at the bottom of the secondary eclipse, which is total. Photometric light curve solutions were obtained using the Wilson-Devinney program. The solution results describe a semidetached configuration with the cool K8 secondary star filling its Roche lobe. This is a near contact binary with the F0 primary star having a filling factor of over 99%. The mass ratio is M2 / M1 = 0.32 and the orbital inclination is near 90°. A period analysis using 29 minima timings resulted in updated ephemerides and revealed an orbital period that is decreasing at a rate of 2.5 × 10^–7 d yr^–1.