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Paper: |
AGB Mass-Loss Characteristics: Rates, Temporal Variations, and Geometries |
Volume: |
445, Why Galaxies Care about AGB Stars II: Shining Examples and Common Inhabitants |
Page: |
253 |
Authors: |
Schöier, F. L.; Ramstedt, S.; Maercker, M.; Olofsson, H. |
Abstract: |
The successful modelling (at various degrees of sophistication) of
circumstellar emission from the vast majority of AGB stars, assuming
a spherically symmetric envelope, suggests that pronounced axi- or
non-symmetric mass loss is not a common phenomenon among AGB stars.
Significant deviations from spherical symmetry have been detected
which, in at least some cases, might be an effect of a binary system.
Temporal modulations of the mass-loss rate are also present, at least
during the later carbon star evolutionary phase, where (more or less
periodic) variations are observed on various time-scales. We present
a summary of the various morphological structures observed around
AGB stars and their interpretation based on radiative
transfer modelling. |
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