Paper: astro-ph/0507429
Date: Tue, 19 Jul 2005 04:37:59 GMT (13kb)

Title: First Ultraviolet Spectrum of a Brown Dwarf: Evidence for H_2
Fluorescence and Accretion

Authors: John E. Gizis, Harry L. Shipman, James A. Harvin
Comments: 8 pages, to appear in Astrophysical Journal Letters
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We analyze an HST/STIS ultraviolet spectrum of the young brown dwarf 2MASSW
J1207334-393254, a member of the ten million-year old TW Hya Association that
has a planetary-mass companion. We detect and identify numerous emission lines.
CIV and other ions are seen that arise in hot gas. We identify a series of
lines with Lyman-pumped H_2 molecular lines, indicating that cool gas is also
present. Overall, this substellar object shows many of the same characteristics
as classical T Tauri stars. We interpret our results as direct evidence of
accretion from a circumstellar gas disk, consistent with previous claims. The
lack of SiIV emission from the accreting gas indicates that silicon has been
depleted into grains.

\\ ( http://arXiv.org/abs/astro-ph/0507429 , 13kb)