A photometric study of the near contact binary star GK Cep

Photoelectric observations of the eclipsing binary GK Cep (BV 382) have been carried out in B and V colors at the Ege University Observatory. Using the (O-C) residuals formed by the photoelectric minima times, an orbital period study of the system was performed. It is confirmed that the sinusoidal (O-C) variation corresponds to a secular period change caused by the light time effect due to an unseen third body in the system. The observed photoelectric light curves of the system were analyzed with the methods of Wilson-Devinney. Simultaneous solutions were made using the radial velocity curves of Bartolini et al. (1965). The system was found to be detached, but not far from the contact phase. The absolute parameters of the system were also deduced. Both compronents are on the Main Sequence.