PI: David A. Weintraub, Vanderbilt University, email@example.com
Address: Physics Department, Box 1807 Station B, Nashville, TN 37235, USA
CoI: Joel H. Kastner, RIT, Carlson Center for Imaging Science
CoI: Jeffrey S. Bary, Vanderbilt University
Title: Using Emission from Molecular Hydrogen Gas to Measure Masses of Circumstellar Disks of T Tauri Stars
Abstract: The persistence of H_2 in circumstellar disks for at least 10^7 yr is required, according to standard models of planet formation, in order for giant planets to form; yet, disks around T Tauri stars become undetectable - via measurements of molecular CO and thermal continuum emission - after only a few million years. Thus, in order to determine whether the circumstellar disks of T Tauri stars are either dispersed or accretionally evolved after 10^7 yr, direct observations of H_2 gas are required. As part of our research program to acquire and interpret such observations, we propose to use Phoenix to observe v=1\rightarrow0 S(1) ro-vibrational line emission of H_2 at 2.1218 (micron) towards a variety of X-ray identified T Tauri stars in the eta Chamaeleon cluster and to obtain very high signal-to-noise measurements of the previously detected, apparently double-peaked H_2 line seen toward LkCa 15 and bright, broad line seen toward GM Aur. In the eta Cha observations, we seek direct evidence for the presence of H_2 gas residing in the circumstellar disks associated with T Tauri stars. In the LkCa 15 and GM Aur observations, we seek to establish a fundamental baseline for understanding and interpreting all 2.1218 (micron) observations of H_2 around T Tauri stars. These observations will lead to improved estimates of the masses of these disks and a better understanding of how often such disks survive long enough to permit planet formation to occur.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360