First photometric analysis of magnetic activity and orbital period variations for the semi-detached binary BU Vulpeculae

PASJ: Publications of the Astronomical Society of Japan

Wang, Jingjing¹  Liu, Liang¹  Tian, Xiaoman²  Zhang, Bin²  Yu, Jing³ 

[1] China University of Petroleum–Beijing at Karamay, Anding Road 355, 834000 Karamay, P.R. China;Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650011, P.R. China;Yunnan Observatories, Chinese Academy of Sciences, P.O. Box 110, 650216 Kunming, P.R. China

关键词: stars: activity;    (stars:) binaries: eclipsing;    stars: evolution;    stars: solar-type;   

DOI  :  10.1093/pasj/psy064

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

Four sets of multi-color CCD photometric observations of the close binary BU Vul were carried out for four successive months in 2010. From our observations, there are obvious variations and asymmetry of light curves on the timescale of a month, indicating high-level stellar spot activity on the surface of at least one component. The Wilson–Devinney (2010) program was used to determine the photometric solutions, which suggest that BU Vul is a semi-detached binary with the cool, less massive component filling with the critical Roche lobe. The solutions also reveal that the spots on the primary and the secondary have changed and drifted in 2010 July, August, and September. Based on analysis of the O − C curves of BU Vul, its orbital period shows a cyclic oscillation (T3 = 22.4 yr, A3 = 0.0029 d) superimposed on a secular increase. The continuous increase is possibly a result of mass transfer from the less massive component to the more massive one at a rate of dM/dt = −2.95 × 10−9 M⊙ yr−1. The cyclic variation maybe be caused by the presence of a tertiary companion with extremely low luminosity. Combined with the distortions of the light curve on 2009 November 4, we infer that BU Vul has two additional companions in a quadruple system.

【 授权许可】

CC BY