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Mass-loss properties of S-stars on the AGB

S. Ramstedt·F. L. Schoeier·H. Olofsson·A. A. Lundgren
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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 2E-7 Msun/yr, and resembles values obtained for similar samples of M-stars and carbon stars. Possibly, there is a scarcity of high-mass-loss-rate (>=1E-5 Msun/yr) S-stars. The distribution of envelope gas expansion velocities is similar to that of the M-stars, the median is 7.5 km/s, 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.

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S. Ramstedt, F. L. Schoeier, H. Olofsson, A. A. Lundgren. 2006-05-26. Mass-loss properties of S-stars on the AGB. https://doi.org/10.1051/0004-6361%3A20065285

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