The supergiant OH stars S Per and AH Sco. Conditions for OH emission in circumstellar envelopes.
Abstract
Summary. A search for 18 cm OH emission in intermediate age ( years) M supergiants is presented. The spectra obtained for S Per and AH Sco show that the 1665/1667 MHz lines are stronger than the 1612 MHz line (not detected in AH Sco) and that the main line emission is unusually extended: A V > 30 km s - For S Per which belongs to the Per OB1 association, the symmetry of the two OH peaks with respect to the stellar velocity suggests that its envelope is spherically expanding. For AH Sco we derive a distance of about 2.6 kpc. It is perhaps in the Sagittarius spiral arm. A discussion of the conditions for OH emission and of the structure of circumstellar envelopes is given. A search for the hydroxyl radical in young objects is also presented. Key words: OH emission - OH formation - super- giant stars
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- January 1977
- Bibcode:
- 1977A&A....54..593B
- Keywords:
-
- Hydroxyl Emission;
- Infrared Stars;
- Interstellar Masers;
- M Stars;
- Stellar Envelopes;
- Supergiant Stars;
- Astronomical Spectroscopy;
- Interstellar Radiation;
- Late Stars;
- Radio Spectra;
- Ultrahigh Frequencies;
- Astrophysics