Observations of directly imaged and transiting exoplanets and brown dwarfs reveal the wide-spread presence of condensate clouds. These clouds profoundly influence the energy transport through ultracool atmospheres and impact their pressure-temperature profiles. Yet, the structure and properties of these cloud layers remain mostly unknown and pose one of the great challenges in understanding ultracool atmospheres. I will show how HST’s and Spitzer’s stability and sensitivity allow us to address this challenge via an exciting new observational approach. With time-resolved spectroscopy and photometry – rotational phase mapping — we are exploring the longitudinal structure of clouds; with multiple epoch observations we are following the evolution of the cloud cover, opening a new window of atmospheric dynamics, and with the powerful combination of simultaneous HST and Spitzer observations we are exploring the vertical structures of the atmospheres.
Daniel Apai (University of Arizon)
March 18, 2016
14:00 - 15:00