Failed Stars and Super Planets A Report Based on the January 1998 Workshop on Substellar-Mass Objects (1998) / Chapter Skim
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3 Theoretical Models of SMO Structure and Atmosphere
3 Theoretical Models of SMO Structure and Atmosphere
Pages 27-34
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From page 27... ...
These characteristics approximately replicate those inferred from spectra of Gliese 229B, the first brown dwarf to be unambiguously detected and the only one bright enough and readily separable from its binary companion to allow for spectroscopic study of its structure. TABLE 3.1 Bulk Characteristics of Jupiter and a Typical Brown Dwarf Jupiter Brown Dwarf Mass (Jupiter masses)
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From page 28... ...
It is possible that NN, is depleted from the upper atmosphere of Gliese 229B as a result of convection: hot underlying gas transported to the photospl~ere at rates fast enough to quench in abundances of a deeper atmospheric level. The upper atmosphere would then be in disequilibrium and contain compounds native to this hotter and deeper level.
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From page 29... ...
The spectrum resembles that of Jupiter far more than any other celestial object because it contains deep absorption features due to methane (CH4) and water (H2O)
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From page 30... ...
MODEL ATMOSPHERES AND SYNTHETIC SPECTRA OF BROWN DWARFS France Allard Wichita State University Accurate model atmospheres are necessary for the calculation of synthetic spectra and tile quantitative derivation ofthe surface chemical composition. They form a necessary step in the transformation from observed colors to theoretical effective temperatures.
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From page 31... ...
INTERIOR AND EVOLUTIONARY MODELS OF BROWN DWARFS Adam Burrows University of Arizona Doppler spectroscopy has recently revealed ~20 giant planets and brown dwarfs orhitino nearby stars, including ~ Bootis, S 1 Pegasi, v Andromedae, 55 Cancri, p Coronae Borealis 70 Virginis, 16 Cygni B and 47 Ursae Majoris.
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From page 32... ...
fluxes are generally higher than blackbody values, He and CHIN absorption features in the L' band decrease its importance relative to Hand H As a consequence of the increase in atmospheric pressure with decreasing effective temperature, the anomalously blue ]
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From page 33... ...
9. The existence of an interior radiative zone seems to be a generic feature of substelIar objects with effective temperatures between ~200 and 1000 K, and might also obtain for effective temperatures below ~200 K
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From page 34... ...
This yields the determination of the halo stellar density and halo/disk normalization down to the brown dwarf limit. Extrapolation into the substellar regime yields the maximum contribution of brown dwarfs to the spheroid and dark halo populations and to the galactic dynamical mass.
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