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Jamie Williams
University of Missouri--Saint Louis 2009
Physics and Astronomy
Advisor: Dr. Erika Gibb
Abstract
We analyzed spectra of eight Young Stellar Object's (YSO's) located in the Rho Ophiuchus star forming region to determine the column density of CO2 ice in the envelope and disk surrounding the YSO's. The data for these sources were gathered using the Infrared Spectrometer (IRS) on the Spitzer Space Telescope (Houck, J., et al., 2004), a space-based telescope in a 'trailing Earth orbit'. We obtained high resolution data from the Spitzer archive for our sources, and reduced the data using the Spitzer pipeline and SMART (Higdon et al. 2004). In particular, we focused on the short high mode (SH), which covers the 10-19µm region. CO2 at 15.2 µm was found toward most of the sources, and analyzed by fitting laboratory spectra to the optical depth spectrum. The column density was calculated by integrating over the optical depth, and dividing by the band strength, A. In addition to these column densities, the shapes of the individual ice profiles were compared to one another. Since the observed profiles are dependent on temperature and composition, profile comparisons provide an indication of thermal processing as well as composition. Cold CO2 ice was found in six out eight sources all with similar band profiles and similar apolar and polar components.
Jamie Williams is from Saint Louis, Missouri and is studying physics and astronomy at a senior level at the University of Missouri-St.Louis.
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