Program: GN-2015B-LP-3

The study of representative exoplanet atmospheres is the next important step for improving our knowledge of exoplanetary physics. Exoplanet observations so far have revealed an intriguing picture: some exoplanets sharing similar physical properties (mass, radius, temperature) exhibit clouds while others don’t. This diversity needs to be understood, as does the origin and nature of such clouds. These questions are fundamental, since clouds drive the planet’s energy budget and significantly affect our ability to probe deeper exoplanet atmospheres. We propose to conduct the first survey of exoplanet atmospheres dedicated to the detection and study of clouds. The nature of these clouds will be constrained by measuring the condensate sizes using their main spectral signature: Mie scattering. The blue optical is the only spectral region where the scattering power law from clouds (lambda^-4) can be directly detected and measured. Thus, we propose an intensive survey of four exoplanet archetypes with GMOS-N B600, providing the high spectrophotometric precision required to study clouds. The proposed spectra, combined with previous R150 observations, will pave the way for future exoplanet characterization.