1. The evolution of brown dwarf's infrared spectroscopic properties IR and Sub-mm Spectroscopy - a New Tool for Studying Stellar Evolution SpS1, Session 8, Thursday Aug 6th, 9h-9h35 France Allard & Isabelle Barrafe Directrices de Recherche, CNRS Centre de Recherche Astrophysique de Lyon
2. Burning: from VLM stars to planets stars brown dwarfs Planemos (planetary mass objects) = 3.5 10 6 K = 1 10 6 K = 2.4 10 6 K
8. 2200K 1800K 1000K Teff from M ---> L -----> T dwarf Baraffe et al. ‘1998,2003; Chabrier et al. 2000 , Allard et al. 2001 Marley et al. 2000, 2002; Burrows et al. 2003, 2006 Formation and settling of « dust » in brown dwarf atmospheres
12. 0.1 Myr log 10 g = 2.5 log 10 g = 3.0 H 2 ! Uncertainties at young ages!
13. Clouds in brown dwarfs Fergley & Lodders, Astrophysics Update 2, edited by John W. Mason. ISBN 3-540-30312-X. Published by Springer Verlag, Heidelberg, Germany, 2006, p.1 http://arxiv.org/abs/ astro-ph/0601381
16. Effects of grains on atmosphere profiles: « green house » effect which heats up the outer layers
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20. Dynamical Transport N 2 and CO is transported from inner/warmer regions of the atmosphere, depleting NH 3 (N 2 ) and CH 4 (CO) Saumon et al. (2003)
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22. 3D Radiation Hydrodynamics Freytag & Allard 2009 3D radiation hydrodynamical simulation of a brown dwarf (T eff =1500K, logg=5, type L) atmosphere cube (340 x 340 x 113 km 3 ). Runtime: 1.8 hours stellar time (about 3 months on 6 processors). Time step: 0.18 sec (6 hydro steps, 1 viscosity step, 1 source step, 1 radiation step). Color coded (right) is the dust concentration (Mg 2 SiO 4 ), and (left) the entropy of the convective zone. The model does not include rotation effects (next step when the model is relaxed). Awaits financial support.
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24. TVLM513-46546 Hallinan et al. (ApJ 663, L25, 2007) Time series of the radio emission detected with the VLA from the M9 dwarf TVLM 513-46546. Every 1.958 hrs a periodic pulse is detected when extremely bright beams of radiation originating at the poles sweep Earth when the dwarf rotates. This dim dwarf is producing radio emission which is thousands of times brighter than any ever detected from the Sun. CREDIT: Hallinan et al., NRAO/AUI/NSF Animated gif of the radio emission from the M9 dwarf TVLM 513-46546 detected with the VLA at 8.44 GHz . The time between each bright pulse corresponds to 1.958 hrs , which is the period of rotation of the dwarf . CREDIT: Hallinan et al., NRAO/AUI/NSF
