V965 Cephei revisited: evidence for a binary system

Abstract

We extended the $O-C$ diagram for V965 Cep with all currently available observations in the Johnson V filter and added unfiltered ones. The new, up-to-date $O-C$ diagram shows that the seeming period change previously revealed by the author does not occur uniformly. Instead, the near-parabolic part of the $O-C$ diagram can be a part of a periodic curve. This could be a sign of the second body in the system. Based on our observations, we also estimated the $B-V$ index of the star to be $0.48 \pm 0.05$ at maximum brightness and $0.57 \pm 0.05$ at minimum brightness.