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R. Y. Shuping, T. P. Snow (CASA, Univ. of Colorado), J. E. Chiar (NASA/Ames)
This poster will display the results of our CO infrared (IR) absorption line analysis for selected sightlines in two nearby molecular clouds. We have observed the 4.6 \micron\ (v = 1 - 0) gas-phase CO lines at high resolution for the Taurus sources Elias 18 and HD 29647, and for Mon R2 IRS 2, using the CSHELL instrument on NASA's IR Telescope Facility (IRTF). The gas-phase data have been compared to CO ice measurements for the same sightlines yielding direct measures of the CO depletion onto dust grains. The three sightlines sample three very different environments and hence have very different CO depletions. For the HD 29647 line of sight all the CO is gaseous, but for Elias 18, a majority (over 58 %) of the CO is in the form of ices. A detailed analysis of each sightline will be presented using the complementary gas-phase and solid-state data, in an effort to understand the physical transition of CO from gas to dust. Finally, the consequences of our results on molecular cloud masses and star-formation theories will also be addressed.
This research has been funded by NASA.
The author(s) of this abstract have provided an email address for comments about the abstract: shuping@casa.colorado.edu