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G. Mallen-Ornelas (Princeton University and P. Universidad Catolica de Chile), S. Seager (Institute for Advanced Study), H.K.C. Yee (University of Toronto), D. Minniti (P. Universidad Catolica de Chile), M.D. Gladders (Observatories of the Carnegie Institution), S. Ellison (ESO-Chile), T. Brown (High Altitude Observatory), G.M. Mallen (Sociedad Astronomica de Mexico)
We present the first results from a deep search for transiting close-in extrasolar planets around Galactic field stars. Using the MOSAIC II 36'x36' wide-field imager on the CTIO 4m telescope, we monitored a single field near the galactic plane with ~100,000 stars with I<18.2. We took an image every 2.75 minutes throughout 11 nights in June 2001, 6 of which had good weather. Using a custom written data analysis pipeline that includes aperture photometry with sinc-shift centroiding, and iterative relative photometry, we generated lightcurves where the best 37,000 have 0.2%--1% rms. Several lightcurves have shallow flat-bottomed eclipses, which are indicative of a companion that is fully superimposed on the stellar disk. Flat bottomed eclipses allow us to select likely planet transit candidates with no contamination from grazing binaries. Because late M dwarfs, brown dwarfs, and gas giant planets are all of similar sizes, radial velocity measurements are needed to constrain the companion mass. We have obtained VLT+UVES follow-up radial velocity measurements of 3 planet transit candidates. We describe our method and present lightcurves and radial velocity data for our best candidates.