Infrared observations of ices and silicates in molecular clouds. (original) (raw)
NASA/ADS
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Abstract
Spectrophotometric observations from 2 to 4 microns and from 8 to 13 microns of several infrared sources associated with molecular clouds are reported. Narrow absorption features at 3.08 microns, attributed to interstellar ices, appear in all sources with a molecular cloud in the intervening line of sight. All sources showing ice absorptions also show broad absorption features, attributed to cold silicates, from 8 to 13 microns. The observed ice absorption profiles are all quite similar; however, they do not fit in detail Mie theory predictions of extinction for pure H2O or NH3 ices. The ratio of ice-to-silicate optical depths is found to vary, with most sources showing a ratio in the range 0.1-0.4. The ratio of visual extinction to ice absorption is found to increase rapidly from inside to outside the molecular cloud in NGC 2024.
Publication:
The Astrophysical Journal
Pub Date:
August 1976
DOI:
Bibcode:
Keywords:
- Ice;
- Infrared Astronomy;
- Interstellar Matter;
- Molecular Absorption;
- Silicates;
- Absorption Spectra;
- Ammonia;
- Electromagnetic Absorption;
- Interstellar Extinction;
- Mie Scattering;
- Solid Phases;
- Water;
- Astrophysics