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

The Survey for Transiting Extrasolar Planets in Stellar Systems (STEPSS)project is a search for planetary transits in open clusters. In this paper, weanalyze the STEPSS observations of the open cluster NGC 1245 to determine thevariable 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 intrinsicvariability that are potential cluster members, and 29 clear variables that arenot cluster members. None of these variables have been previously identified.We present light curves, finding charts, and stellar/photometric data on thesevariable objects. Several of the interacting binaries have estimated distancesconsistent with the cluster distance determined from isochrone fits to thecolor magnitude diagram. Four stars at the main sequence turnoff of the clusterhave light curves consistent with gamma Doradus variability. If these gammaDoradus candidates are confirmed, they represent the oldest and coolest membersof this class of variable discovered to date.