Optical pumping of circumstellar CO masers
Abstract
The influence of the photospheric line spectrum on the optical pumping of circumstellar CO is investigated. As pump radiation the photospheric spectrum of a cool carbon star (Teff = 2600 K) is considered in particular. This spectrum shows deep absorption lines in the wavelength range of the pump lines (4.6 microns). Of particular importance for the pump process is the velocity difference between the photosphere and the envelope. In a certain parameter range inversion is found for the 2.6 mm line if Delta-v(r) is low, while inversion is found for the 1.3 mm line for large values of Delta-v(r) (about 10 km/s). These findings differ significantly from those of other authors who considered the photospheric spectrum to correspond to that of a black body.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 1991
- Bibcode:
- 1991A&A...245..580P
- Keywords:
-
- Carbon Stars;
- Interstellar Masers;
- Stellar Envelopes;
- Carbon Monoxide;
- Optical Pumping;
- Astrophysics