Survey for Transiting Extrasolar Planets in Stellar Systems. IV. Variables in the Field of NGC 1245

Abstract

The Survey for Transiting Extrasolar Planets in Stellar Systems (STEPSS) project is a search for planetary transits in open clusters. In this paper we analyze the STEPSS observations of the open cluster NGC 1245 to determine the variable-star content of the cluster. Out of 6787 stars observed with V<22, of which ~870 are cluster members, we find 14 stars with clear intrinsic variability that are potential cluster members and 29 clear variables that are not cluster members. None of these variables have been previously identified. We present light curves, finder charts, and stellar/photometric data on these variable objects. Several of the interacting binaries have estimated distances consistent with the cluster distance determined from isochrone fits to the color-magnitude diagram. Four stars at the main-sequence turnoff of the cluster have light curves consistent with γ Doradus variability. If these γ Doradus candidates are confirmed, they represent the oldest and coolest members of this class of variable discovered to date.