NEW ASTRONOMY, vol.46, pp.73-77, 2016 (SCI-Expanded)
We present the orbital period study and the photometric analysis of the contact binary system V728 Her. Our orbital period analysis shows that the period of the system increases (dP/dt = 1.92 x 10(-7)dyr(-1)) and the mass transfer rate from the less massive component to more massive one is 2.51 x 10(-8) M(circle dot)y(-1). In addition, an advanced sinusoidal variation in period can be attributed to the light-time effect by a tertiary component or the Applegate mechanism triggered by the secondary component. The simultaneous multicolor BVR light and radial velocity curves solution indicates that the physical parameters of the system are M-1 = 1.8M(circle dot), M-2 = 0.28M(circle dot), R-1 = 1.87R(circle dot), R-2 = 0.82R(circle dot), L-1 = 5.9L(circle dot), and L-2 = 1.2L(circle dot). We discuss the evolutionary status and conclude that V728 Her is a deep (f = 81%), low mass ratio (q = 0.16) contact binary system. (C) 2015 Elsevier B.V. All rights reserved.