Abstract
We obtained high-quality optical images with VIMOS at the ESO VLT, in order to get very precise lightcurves during the transits of 10 OGLE candidates. Our photometry is about 10 times more precise and 100 times more frequent than the OGLE photometry, and that is achieved accumulating more photons faster, using the large telescope. With about 100 points in the flat portion of the transit plus a similar number of points before and after, we could measure the eclipse amplitudes with a precision of 0.0001 mag and also accurate transit durations.
The candidates have been confirmed as faithful planets or brown dwarfs or pre-screened carefully as good candidates as done in our previous work using low dispersion spectroscopy and near-IR photometry.
The final products of our work are: 1) Determination of the mean transit times and of the times of ingress-egress. 2) Precise estimate of the transit geometry (impact parameter of the transit and the orbital inclination angle). 3) Accurate measurement of the amplitude of the transit, leading to a precise planetary radius measurement.