Millimagnitude photometry for transiting extrasolar planetary candidates

Abstract

Aims. We used VLT/VIMOS images in the V band to obtain light curves of the extrasolar planetary transits OGLE-TR-111 and OGLE-TR-113 and the candidate planetary transits: OGLE-TR-82, OGLE-TR-86, OGLE-TR-91, OGLE-TR-106, OGLE-TR-109, OGLE-TR-110, OGLE-TR-159, OGLE-TR-167, OGLE-TR-170, OGLE-TR-171. Methods. Using difference imaging photometry, we were able to achieve millimagnitude errors in the individual data points. We present the analysis of the data and the light curves by measuring transit amplitudes and ephemerides and by calculating geometrical parameters for some of the systems. Results. We observed nine OGLE objects at the predicted transit moments. Two other transits were shifted in time by a few hours. For another seven objects we expected to observe transits during the VIMOS run, but they were not detected. Conclusions. The stars OGLE-TR-111 and OGLE-TR-113 are probably the only OGLE objects in the observed sample to host planets, with the other objects being very likely eclipsing binaries or multiple systems. In this paper we also report on four new transiting candidates which we have found in the data