Clouds in brown dwarfs and giant planets

Daniel Apai (U Arizona), Stanimir Metchev (Stony Brook U), Jacqueline Radigan (U Toronto)


Periodic variability in cool brown dwarfs, likely caused by uneven cloud coverage, provides a novel probe of the horizontal and vertical cloud structure in substellar atmospheres.  It has already enabled model-independent constraints on the dissipation of clouds across the L/T transition.  In addition to understanding cloud structure, mapping the time evolution of cloud-induced variability in brown dwarfs provides a novel way to study atmospheric circulation in the high-gravity, rapidly rotating regime that is inaccessible from observations of hot Jupiter-type transiting planets.

The splinter session shines a timely spotlight on this new approach to exploring ultra-cool atmospheres enabled by recent breakthroughs in precision photometry.  These results represent the realization of over a decade's worth of searches for unambiguous cloud-related variability in late-M, L and T dwarfs and a significant community investment in resources. The pressing interest in unraveling the cloud structure of directly imaged extrasolar planets and cool brown dwarfs makes the session broadly relevant to the wider substellar astrophysics community. 


Program                  25 JUN 2012                 3:00–5:45pm

15:00   Craig Stark & Christiane Helling (U St Andrews), invited review

              Theory of Clouds

15:20   Étienne Artigau (U Montréal), invited review

              Multi-Year Monitoring of SIMP 0136

15:40   Aren Heinze (Stony Brook U)

              Towards an Understanding of Brown Dwarf Weather:

              First Results from a Spitzer/IRAC Variability Survey

15:50   Stuart Littlefair (U Sheffield)

              Variability at the Warm End: Lessons from TVLM513–46546

16:00   Discussion

16:15                                  Coffee Break

16:30   Jacqueline Radigan (U Toronto), invited review

              Ground-Based and Spitzer Photometry of Varying Brown Dwarfs

16:50   Caroline Morley (UCSC)

              Sulfide Clouds in Cool Brown Dwarf Atmospheres

17:00   Derek Homeier (CRAL-ENS Lyon)

              Dust Dynamics in a Hydrodynamically Driven Cloud Model

17:10   Andrew Skemer (U Arizona)

              First Light LBT AO Images of HR 8799 bcde at 1.6 and 3.3 microns:

              New Discrepancies between Young Planets and Old Brown Dwarfs

17:20   Discussion and Wrap-up

Invited talks are 15 min + 5 min for questions.

Contributed talks are 7 min + 3 min for questions.


Image: art by Jon Lomberg

Periodic brightness modulations in a T2.5 brown dwarf (Artigau et al. 2009).