Molecular Hydrogen and Lyman-alpha Emission in FUV Spectra of CTTSs
Abstract
The presence and structure of gas in circumstellar disks around young stars has profound implications on the formation and early evolution of planets. We use HST/STIS and FUSE spectra of a small sample of CTTSs to study fluorescent H2 emission, pumped by Lyman-alpha. We find that the H2 traces 2500 K gas at or near the disk surface within 2 AU of the central star. These H2 lines allow us to indirectly measure Lyman-alpha emission, which is typically obscured by H I absorption in our line of sight to the star. Lyman-alpha emission contributes 80-90% of the total FUV emission from CTTSs, and alters the disk chemistry.
- Publication:
-
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 2004
- Bibcode:
- 2004AAS...20515604H