| Description |
Herschel has revealed that wind-ISM interaction regions and detached
rings occur frequently around evolved stars. These interaction regions
are observed to yield various shapes and sizes which can be divided in
four main morphological classes. To first order the distance between
the bow shock apex and the star is set by the stellar properties (mass-loss
rate, wind velocity, peculiar motion) and the properties of the local ISM
(density and temperature).
The primary objective of this proposal is to characterize and understand
the interaction of stellar mass-loss with its immediate surroundings by
studying the direct emission cold dust as it is trapped in the interaction
region between the stellar wind and the ISM. Thus we can follow the fate of
circumstellar dust, use the observed morphologies as tracers of the ISM
and of the later stages of stellar evolution. Also we aim to elucidate effects
of magnetic fields, binarity, and circumstellar chemistry on the shaping of
these interaction .bow shock. regions.
Herschel is uniquely equiped to trace the cold dust that is trapped in the
studied interaction zones. These goals can be achieved best by performing
a sufficiently comprehensive PACS imaging survey of nearby AGB stars. |
