0 Assigned ID: 941 ----- Attempting Submission 1 (Fri Apr 11 22:18:38 GMT 2014) ----- HST Phase I Proposal 941 (phase1-AR.apt) successfully submitted. ----- Attempting Submission 2 (Fri Apr 11 22:19:48 GMT 2014) ----- HST Phase I Proposal 941 (phase1-AR.apt) successfully submitted. ----- Attempting Submission 3 (Fri Apr 11 22:42:19 GMT 2014) ----- HST Phase I Proposal 941 (phase1-AR.apt) successfully submitted. ----- Attempting Submission 4 (Fri Apr 11 22:48:07 GMT 2014) ----- Over 130 HST orbits and 3000 Spitzer hours have been dedicated to observing variability in the emission of brown dwarfs, but we do not yet understand the physical processes that cause brown dwarf weather. The aim of the proposed work is to build the modeling tools to turn brown dwarf light curves into constraints on their atmospheric physics. Light curves of variable brown dwarfs are not simple sinusoids, but show spectral dependence in both amplitude and phase. Many objects exhibit evolution in the amplitude or shape of the light curve from one observation to another, indicating evolution of weather patterns. These complexities mean that while the two likely causes of variability--patchy clouds and temperature perturbations--should have distinct spectral signatures, the data are proving challenging to explain with simple prescriptions. Our tool to understand this extrasolar weather is to use a retrieval technique to extract the physical parameters that cause brown dwarf variability, directly from brown dwarf spectra. Using this tool with the information-rich HST data, we probe the temperature and cloud structure in multiple spatial dimensions as well as the time-evolution of these structures. These constraints provide crucial information for the development of atmospheric dynamical models, currently in their infancy for brown dwarfs. The retrieval technique we propose will allow us to leave the confines of pre-calculated grid models and measure the causes of brown dwarf weather directly from spectra. This tool will provide the information necessary to understand the atmospheric physics underlying warm substellar weather, decades before we can study weather on exoplanets. COOL STARS Default Small false false false false true SUPPORTED