Mass loss is a fundamental, observationally well-established feature of AGB stars but many aspects of this process still remain to be understood. To date, self-consistent dynamical models of dust-driven winds reproducing the observed mass-loss rates seem only possible for M-type stars if the grains in the close circumstellar environment grow to larger sizes than previously assumed. In order to study the grain-size distribution where the mass loss is initiated, high-spatial-resolution interferometry observations are necessary. We have observed two M-type stars using the VLTI/MIDI instrument to constrain the dust-grain sizes through modeling the 10-micron silicate feature. Complementary observations are scheduled and we will present preliminary results.
@article{arxiv.1011.2068,
title = {A possible solution to the mass-loss problem in M-type AGB stars},
author = {H. Olofsson and S. Ramstedt and S. Sacuto and M. Maercker and S. Höfner and F. Kerschbaum},
journal= {arXiv preprint arXiv:1011.2068},
year = {2010}
}
Comments
To appear in the proceedings of Why Galaxies Care About AGB stars II