Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 2G014

Towards the first transmission spectrum of a gas giant transiting an M-dwarf

Delrez, L. (Institut d’Astrophysique et de Géophysique de l’Université de Liège, allée du 6 Août 17, 4000 Liège, Belgium)
Gillon, M. (Institut d’Astrophysique et de Géophysique de l’Université de Liège, allée du 6 Août 17, 4000 Liège, Belgium)
Lendl, M. (Observatoire astronomique de l’Université de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland)
Jehin, E. (Institut d’Astrophysique et de Géophysique de l’Université de Liège, allée du 6 Août 17, 4000 Liège, Belgium)
Anderson, D. (Astrophysics Group, Keele University, Staffordshire ST5 5BG, UK)
Demory, B.-O. (Department of Earth, Atmospheric and Planetary Sciences, MIT, 77 Massachusetts Avenue, Cambridge, MA 02139, USA)
De Wit, J. (Department of Earth, Atmospheric and Planetary Sciences, MIT, 77 Massachusetts Avenue, Cambridge, MA 02139, USA)
Hellier, C. (Astrophysics Group, Keele University, Staffordshire ST5 5BG, UK)
Triaud, A. (Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA)
Queloz, D. (Observatoire astronomique de l’Université de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland)

Abstract:
At the forefront of comparative exoplanetology, the atmospheric characterization of transiting exoplanets is revealing the intimate nature of these new worlds. In this exciting context, we are currently conducting a VLT observing campaign on a rare exoplanet specimen, WASP-80b, a gas giant in close orbit around a bright nearby M-dwarf. Even if this planet belongs to the hot-Jupiter population, it is actually more ‘warm’ than ‘hot’ with an estimated equilibrium temperature of only 800K. We present here some preliminary results of this program which consists in monitoring four transits of WASP-80b with the FORS2 instrument in multi-object spectroscopic mode in ESO phase 91. Through this approach, our goal is to precisely measure the transmission spectrum of the planet between 740 and 1070 nm in order to constrain the thermal structure and scacering properties of the planetary atmosphere. Furthermore, we will use the water features located around 950 nm to constrain the water mixing ratio in the atmosphere of this peculiar hot Jupiter.

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