PI: Katelyn Allers, Bucknell University, firstname.lastname@example.org
Address: Department of Physics and Astronomy, Lewisburg, PA, 17837, U.S.A
CoI: Andrew Skemer, University of Arizona (Astronomy)
CoI: Jacqueline Faherty, Carnegie Institution of Washington (Terrestrial Magn.)
CoI: Mark Marley, NASA Ames
Title: Clouds and Non-Equilibrium Chemistry in Brown Dwarf and Exoplanet Atmospheres
Abstract: Current models for directly-imaged exoplanets require non-equilibrium chemistry and thick or patchy clouds to explain their spectral peculiarities. Our ability to test models of directly-imaged exoplanets, however, is hampered by the small number of known directly imaged exoplanets and by the difficulty of obtaining high S/N observations. We have identified a sample of young brown dwarfs with ages, temperatures and masses similar to directly-imaged exoplanets. We propose 3-4 micron spectroscopy of these young brown dwarfs to test model atmospheres for a broad range of age and temperature. The 3-4 micron region is ideal for these tests for a number of reasons: The 3.3 micron methane feature emerges at lower methane abundance than lines at shorter wavelengths, allowing us to test non-equilibrium chemistry and cloud patchiness. The spectral slope from 3-4 microns is sensitive to the cloud thickness and dust grain size. In combination with in-hand near-IR spectroscopy, our proposed observations will provide the most stringent tests of models for young, planetary-mass atmospheres conducted to date, and will lay critical groundwork for interpreting upcombing results from GPI, SPHERE, LEECH, P-1640, and eventually JWST.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360