NOAO >   Observing Info >   Approved Programs >   2003B-0124

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Proposal Information for 2003B-0124


PI: David A. Weintraub, Vanderbilt University, david.weintraub@vanderbilt.edu
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.


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