Résumé / Abstract Journal-club_Postdoc

Journal-club Postdoc

« From Brown Dwarfs to Exoplanets: A study of weather and composition »

Paul Wilson

In this talk I will present highlights from my recent work on the
atmospheres of brown dwarfs and exoplanets. As brown dwarfs age, and as a
result cool with time, their atmospheres undergo a plethora of physical
and chemical changes. Nowhere along the brown dwarf spectral sequence are
these changes so abrupt at at the L-T transition where a rapid shift from
the red to the blue colours is observed over a narrow effective
temperature range. Patchy clouds might be the explanation for this change.
The consequence of patchy clouds would be variations in the observed flux
due to the rotation and evolution of the clouds. I will present results
from the Brown dwarf Atmosphere Monitoring (BAM) project, a large near-IR
photometric monitoring campaign covering 69 ultracool L & T type brown
dwarfs.

Transiting hot-Jupiters provide an excellent opportunity to detect and
characterise exoplanetary atmospheres. To be able to perform a wide scale
comparative exoplanetology however, we have to observe targets which are
too faint for the Hubble Space Telescope. To do this, we use the GTC
telescope together with unique tunable filters capable of precision
narrowband photometry at specific wavelengths. This technique coupled with
the use of the worlds largest optical telescope allows us to obtain
photon-limited sub-mmag narrowband transit spectrophotometry, capable of
detecting Na, K, TiO and other important atmospheric species.
I will present the technique being used as well as some of the results
from this survey.
mercredi 29 octobre 2014 - 11:00
Salle Entresol Daniel Chalonge, Institut d'Astrophysique
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