The infrared band strengths of CH_3OH, NH_3 and CH_4 in laboratory simulations of astrophysical ice mixtures
Abstract
Results from groundbased observations and the Infrared Space Observatory (ISO) indicate that CH_3OH, NH_3 and CH_4 are important constituents of interstellar ice mantles. In order to accurately calculate the column densities of these molecules, it is important to have good measurements of their infrared band strength in astrophysical ice analogs. Band strength measurements of CH_3OH and CH_4 are presented showing that they depend only weakly on the composition of the ice matrix and the temperature. On the other hand, the umbrella mode of NH_3 does show a significant decrease when dilluted in H_2O ice. For this reason the original estimates of the abundance of NH_3 in interstellar ice need to be revised upward by 30%.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- June 1999
- Bibcode:
- 1999A&A...346..990K
- Keywords:
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- METHODS: LABORATORY;
- ISM: ABUNDANCES;
- ISM: DUST;
- EXTINCTION;
- ISM: MOLECULES;
- INFRARED: ISM: LINES AND BANDS