Mass-loss properties of S-stars on the AGB
Abstract
We have used a detailed non-LTE radiative transfer code to model new APEX CO(J = 3 → 2) data, and existing CO radio line data, on a sample of 40 AGB S-stars. The derived mass-loss-rate distribution has a median value of 2 × 10-7~M⊙ yr-1, and resembles values obtained for similar samples of M-stars and carbon stars. Possibly, there is a scarcity of high-mass-loss-rate (≥10-5~M⊙ yr-1) S-stars. The distribution of envelope gas expansion velocities is similar to that of the M-stars, the median is 7.5 km s-1, while the carbon stars, in general, have higher gas expansion velocities. The mass-loss rate correlates well with the gas expansion velocity, in accordance with results for M-stars and carbon stars.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- August 2006
- DOI:
- 10.1051/0004-6361:20065285
- arXiv:
- arXiv:astro-ph/0605664
- Bibcode:
- 2006A&A...454L.103R
- Keywords:
-
- stars: AGB and post-AGB;
- stars: circumstellar matter;
- stars: late-type;
- stars: mass-loss;
- Astrophysics
- E-Print:
- Accepted for publication in the A&