Radio and millimeter observations of circumstellar envelopes.
Abstract
Circumstellar chemistry has been confined largely to analysis of a few dozen molecules in the envelope of one carbon-rich star, IRC +10216. A new generation of large millimeter wavelength telescopes promises to broaden the data base to include many other stars and additional molecules. Carbon-monoxide emission has already been detected from approximately 130 stars and many of these are prime candidates for chemical studies. The detection of HCN emission in a few oxygen-rich stars was quite unexpected and indicates that nonequilibrium chemical processes are important in at least some circumstellar envelopes. New millimeter wavelength interferometers can measure the spatial distribution of various molecules for comparison with predictions of models for photodissociation, freeze-out on grains, self-shielding, and nonspherical outflow.
- Publication:
-
Astrochemistry
- Pub Date:
- 1987
- Bibcode:
- 1987IAUS..120..345Z
- Keywords:
-
- Interstellar Chemistry;
- Millimeter Waves;
- Radio Spectra;
- Stellar Envelopes;
- Stellar Spectrophotometry;
- Carbon Monoxide;
- Emission Spectra;
- Hydrocyanic Acid;
- Line Shape;
- Reaction Kinetics;
- Astrophysics