Ellipsoidal Variability in the OGLE Planetary Transit Candidates

Abstract

We analyze the photometry of 117 OGLE stars with periodic transit events for the presence of ellipsoidal light variations, which indicate the presence of massive companions. We find that ~50% of objects may have stellar companions, mostly among the short period systems. In our Table 1 we identify a coefficient of ellipsoidal variability for each star, a_{c2}, which can be used to select prime candidates for planetary searches. There is a prospect of improving the analysis, and the systems with smaller ellipsoidal variability will be identified, when the correlations in the OGLE photometry are corrected for in the future, thereby providing a cleaner list of systems with possible planets.