SWS observations of solid C0(2) in molecular clouds

Abstract

We report absorption features of solid CO2 stretching and bending modes in several lines of sight, including embedded young stellar objects and the Galactic Center source Sgr A*. The overall CO2 abundance in ices is similar to 15% relative to H2O. Profile shapes are consistent with the presence of grain mantles with distinct polar (H2O-rich) and nonpolar (CO or CO2-rich) layers. In addition to the normal isotopic form, we report detection of the stretching mode of (CO2)-C-13; the C-12/C-13 ratio is consistent with terrestrial and interstellar values.