Program: GN-2005B-Q-36

We propose to use NIRI on Gemini North to detect the 3.05 micron H20 ice absorption band in 7 edge-on T Tauri circumstellar disks and investigate whether the ices in these disks have been processed. Ices play a critical role in the formation of organic molecules in star forming regions. While the 3.05 micron ice band in molecular clouds can be fit with a pure H20 ice model, the ice bands seen in the envelopes of some young stellar objects show evidence for annealing with other species. To date, only one circumstellar disk has been directly observed to have the 3.05 micron ice feature. Consequently, the question of how much processing goes on within the disk environment has yet to be adequately answered. By fitting the profiles of the observed 3.05 micron H20 ice bands with lab spectra, we will investigate the degree of processing that ice has undergone in circumstellar disks compared to T Tauri star envelopes and the relatively unprocessed dust in molecular clouds.