Abstract

Planetary transits play an important role in the study of extrasolar planets as multi-wavelength observations of planetary transits provide measurements of the planetary transmission spectrum. This in turn encodes information on the planet’s atmospheric composition, and the presence of high-altitude cloud structures. I will present our ongoing observing program targeting several hot giant planets with ground-based facilities, focusing on results obtained with the VLT /FORS2 instrument. We made use of FORS2 ’s multi-object spectroscopy mode, and I will briefly discuss strategies to deal with the instrumental limitations affecting FORS2 . Finally, I will show results for two targets: the 1400 K Saturn WASP -49b, and the more mildly irradiated WASP -80b, a hot Jupiter orbiting a K7V star.