Mapping the atmospheres of brown dwarfs and young giant exoplanets

Benjamin Charnay (LAB Bordeaux)

large-scale spectroscopic surveys such as 4MOST, will open a new era in our understanding of black hole accretion physics.Brown dwarfs and young giant exoplanet are subject to variability and colour changes, known as the L/T transition, fundamental for their thermal evolution. Clouds are expected to be the main driver of the L/T. Using 1D and 3D atmospheric models, we show that clouds play a major role in shaping the atmospheric properties of brown dwarfs, in agreement with the observed variability and L/T transition. A major consequence of our 3D simulations is the preferential cloud formation in the equatorial region, leading to a latitudinal thermal gradient which could impact the atmospheric chemistry. During the talk, I will present a new technique to perform latitudinal mapping using high-resolution spectra. We apply this technique to CRIRES+ observations of the late L-dwarf DENIS J0255-4700 to reveal these latitudinal variations. Finally, I will discuss the potential of this method for current instruments (i.e. VLT-Hirise, CFHT-SPIRou) and future instruments on the ELT (i.e. ANDES, METIS, PCS).