Characterization of Giant Planets and Light Brown Dwarfs Companions on Wide Orbits with VLT/SPHERE

Séminaire IPAG de Mickaël Bonnefoy (IPAG), jeudi 3 mai 2018 à 11h00, salle Manuel Forestini IPAG

The SHINE survey conducted on the SPHERE high contrast imager at VLT is targeting 400-500 nearby stars to characterize the giant planet population beyond 5 AU. Once a companion is resolved, the collection of sub-instrument of SPHERE can uniquely provide its spectrum, photometry, and astrometry from 0.5 to 2.5 µm. Those informations are used to better understand the orbital, physical, and chemical properties of the objects, and in turn to access the formation modes and dynamical evolution of planetary systems.

During the past three years, we have achieved through SHINE a complete characterization of all known bona-fide planets discovered so far (HR8799 bcde, 51 Eri b), as well as some benchmark brown dwarf companions (GJ504b, ...). We also found new systems with peculiar architectures and atmospheric properties. I will describe the most tantalizing (and sometime puzzling) results obtained thus far and explain what they tell us about the atmosphere of giant planets, their connection to brown-dwarf atmospheres, and their origins.