AAS 195th Meeting, January 2000
Session 78. Young Stars, Disks and Planets
Display, Friday, January 14, 2000, 9:20am-6:30pm, Grand Hall

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[78.04] Detection of Quiescent Molecular Hydrogen Gas in the Circumstellar Disk of a Classical T Tauri Star

J.S. Bary, D.A. Weintraub (Vanderbilt Univ.), J.H. Kastner (Carlson Center for Imaging Science)

We have detected emission from quiescent, molecular hydrogen gas in the disk around the classical T Tauri star TW Hya in the 1-0 S(1) line at 2.12183 \mum, through high resolution spectroscopy using CSHELL on NASA's Infrared Telescope Facility. The H2 line emission most likely is the result of excitation in the innermost region of the disk by stellar X-rays. This result demonstrates that X-ray ionization is a viable mechanism for excitation of H2 in the gaseous disks of classical T Tauri stars. In addition, from these high resolution spectra we have measured the radial velocities of three T Tauri stars in the TW Hya Association. We find that the radial velocity of CD-33\circ7795 is very similar to the known radial velocites of both TW Hya and HD 98800. This result lends support to the hypothesis that these stars share a common origin in a now-dispersed molecular cloud.

This work is supported by NASA grants NAG5-8295, NAG5-4428, and GO07861.01-96A to Vanderbilt University.

The author(s) of this abstract have provided an email address for comments about the abstract: bary@hltau.phy.vanderbilt.edu

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