Abstract

Transiting planets play an important role in the study of extrasolar planet atmospheres. Multi-wavelength observations of transits provide measurements of the planetary transmission spectrum, while measurements of occultations allow to constrain the planetary emission, and, if observed at several wavelengths allow access to the planetary emission spectrum. From such observations, information on the planet’s atmospheric composition, the presence of high-altitude cloud structures, and the atmospheres thermal profile can be inferred.

I will present our ongoing observing program targeting hot giant planets with large ground-based facilities. I will discuss in detail a transmission spectrum of the transiting hot Saturn WASP -49b that was obtained with the FORS2 instrument, and discuss strategies to deal with substantial instrument systematics affecting FORS2 . I will further present first results for WASP -43b, which has been observed in occultation with the KMOS instrument, covering the H and K bands.