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| Paper: |
Winds of Binary AGB Stars as Observed by Herschel |
| Volume: |
497, Why Galaxies Care about AGB Stars III: A Closer Look in Space and Time |
| Page: |
181 |
| Authors: |
Mayer, A.; Jorissen, A.; Kerschbaum, F.; Ottensamer, R.; Mečina, M.; Paladini, C.; Cox, N. L. J.; Nowotny, W.; Aringer, B.; Pourbaix, D.; Mohamed, S.; Siopis, C.; Groenewegen, M. A. T. |
| Abstract: |
We present Herschel/PACS observations of the large-scale environments of
binary AGB stars as part of the Mass-loss of Evolved StarS (MESS) sample.
From the literature we found 18 of the objects to be members of
physically bound multiple systems. Several show a large-scale far-IR
emission which differs significantly from spherical symmetry. A probable
cause is the gravitational force of the companion on the stellar AGB
wind and the mass-losing star itself. A spiral pattern is thereby
imprinted in the dusty stellar wind.
The most remarkable structures are found around o Ceti, W Aquilæ,
R Aquarii, and π1 Gruis. The environments of o Cet and W Aql show
a spiral pattern while the symbiotic nature of R Aqr is revealed as two
opposing arms which reflect a nova outburst. The emission around
π1 Gru is dominated by two structures, a disk and an arc, which
are presumably not caused by the same companion. We found evidence that
π1 Gru is a hierarchical triple system in which a close companion
attracts the AGB wind onto the orbital plane and the outer companion
forms a spiral arm.
These far-IR observations underline the role of a companion as a major
external influence in creating asymmetric winds in the AGB phase, even
before the star becomes a planetary nebula (PN). |
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