OH maser pumping by line overlap at 2.8 microns
Abstract
The pumping of OH masers in late-type variable stars by direct stellar radiation of 2.8 microns is studied. Two pumping schemes are suggested based on line coincidences between OH V = 0-1 transitions and strong H2O nu3 transitions. The water molecules perturb the stellar radiation by absorption and thus cool the coinciding OH transitions. It is demonstrated that this cooling is capable of producing strong OH masers in the circumstellar envelopes of late-type variable stars. This model can account for the existence of main-line (Delta F = 0) OH masers, which is hard to explain otherwise.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 1980
- DOI:
- 10.1086/158137
- Bibcode:
- 1980ApJ...239..526C
- Keywords:
-
- Hydroxyl Emission;
- Interstellar Masers;
- Late Stars;
- Stellar Envelopes;
- Variable Stars;
- Water Masers;
- Astronomical Models;
- Near Infrared Radiation;
- Pumping;
- Astrophysics