双星与变星研究组知识库

V409 Hya is a newly discovered W UMa-type binary star with a period of 0.47226 days. Complete light curves in V, 12,, and I bands are presented and analyzed with the W-D (Wilson and Devinney) method. It is discovered that V409 Hya is a deep contact binary with a contact degree of integral = 60.6(+/- 1.4)%. It is an A-type, low-mass-ratio contact binary with a mass ratio of 0.22. The derived orbital inclination (i = 89.8 degrees) indicates that it is a total eclipsing binary and the determined parameters are reliable. By combining several determined times of light minimum with the others compiled from the literature, the period changes of V409 Hya were investigated. The general trend of the (O-C) curve reveals that the period of the binary is increasing continuously at a rate of dP/dt = +5.41(+/- 0.06) x 10(-7) days/year. The continuous period increase can be explained by a mass transfer from the secondary to the primary. As the matter is being transferred, the mass ratio of the binary system is decreasing. After it meets the more familiar criterion that the orbital angular momentum is less than 3 times the total spin angular momentum, the deep contact binary may finally evolve into a rapid-rotating single star. (c) 2014 Published by Elsevier B.V.