Issue |
A&A
Volume 409, Number 2, October II 2003
|
|
---|---|---|
Page(s) | 715 - 735 | |
Section | Stellar atmospheres | |
DOI | https://doi.org/10.1051/0004-6361:20031110 | |
Published online | 17 November 2003 |
Mass-loss from dusty, low outflow-velocity AGB stars*
I. Wind structure and mass-loss rates
1
IRAM, 300 rue de la Piscine, 38406 St. Martin d'Hères, France
2
LERMA, UMR 8112, Observatoire de Paris, 61 Av. de l'Observatoire, 75014 Paris, France
3
Swedish-ESO Submillimetre Telescope, European Southern Observatory, Casilla 19001, Santiago 19, Chile
4
Onsala Space Observatory, 439 92 Onsala, Sweden
5
Observatoire de la Côte d'Azur, BP 4229, 06304, Nice Cedex 4, France
Corresponding author: J. M. Winters, winters@iram.fr
Received:
26
March
2003
Accepted:
14
July
2003
We present the first results of a CO(2–1), (1–0), and 86 GHz SiO
maser survey of AGB stars, selected by their weak near-infrared excess.
Among the 65 sources of the present sample
we find 10 objects with low CO outflow velocities,
km s-1. Typically, these sources show (much)
wider SiO maser features.
Additionally, we get 5 sources with composite CO line profiles, i.e. a narrow
feature is superimposed on a broader one, where both components are
centered at the same stellar
velocity. The gas mass-loss rates, outflow velocities and velocity structures
suggested by these line profiles are compared with the results of
hydrodynamical model
calculations for dust forming molecular winds of pulsating AGB stars.
The observations presented here
give support to our recent low outflow-velocity models, in which only small
amounts of dust are formed. Therefore, the wind
generation in these models is dominated by stellar pulsation.
We interpret the composite line profiles in terms of successive
winds with different characteristics. Our hydrodynamical models,
which show that the wind properties may be extremely
sensitive to the stellar parameters, support such a scenario.
Key words: hydrodynamics / stars: mass-loss / stars: AGB and post-AGB / stars: winds, outflows / radio lines: stars
© ESO, 2003
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.