Differential BVRI light curves of EP And

Using the Wilson-Devinney code, we computed the photometric elements of this system. It was discovered that EP And is a W-type W UMa contact binary system with a mass ratio of q=2.685 and a degree of contact factor f=24.9%, rather than an A-type system.

Combining 28 newly determined times of minimum light derived from 1999 to 2012 with others collected from the literature, a long-term increase (dP/dt=+5.22x10^-8^days/yr) with a sinusoidal variation (A=0.0109days; T=40.89yr) in the orbital period was found. The orbital period secular increases may be interpreted as conservative mass transfer from the less massive component to the more massive one, and cyclic variations of the orbital period may be caused by the light-travel time effect through the presence of a third body.