We present the orbital period study and the photometric analys of the contact
binary system V728 Her. Our orbital period analysis shows that the period of
the system increases (dP/dt=1.92x10^-7dyr^-1) and the mass transfer rate from
the less massive component to more massive one is 2.51x10^-8M_suny^-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 M1=1.8M_sun, M2=0.28M_sun, R1=1.87R_sun, R2=0.82R_sun, L1=5.9L_sun, and
L2=1.2L_sun. We discuss the evolutionary status and conclude that V728 Her is a
deep (f=81%), low mass ratio (q=0.16) contact binary system.Comment: 21 pages, 4 figures, 4 table
