Large-scale environments of binary AGB stars probed by Herschel

Author(s)
Andreas Mayer, Alain Jorissen, Franz Kerschbaum, Roland Ottensamer, Walter Nowotny-Schipper, Marko Mecina, Thomas Posch, Nick L. J. Cox, Bernhard Aringer, Joris A D L Blommaert, Leen Decin, Sophie Van Eck, H.-P. Gail, Martin A. T. Groenewegen, K. Kornfeld, Bart Vandenbussche, Christoffel Waelkens
Abstract

The Mass loss of Evolved StarS (MESS) sample offers a selection of 78 asymptotic giant branch (AGB) stars and red supergiants (RSGs) observed with the PACS photometer on-board Herschel at 70 μm and 160 μm. For most of these objects, the dusty AGB wind is not spherically symmetric and the wind shape can be subdivided into four classes. In the present paper we concentrate on the influence of a companion on the morphology of the stellar wind. Literature was searched to find binaries in the MESS sample, which were subsequently linked to their wind-morphology class to assert that the binaries are not distributed equally among the classes. In the second part of the paper we concentrate on the circumstellar environment of the two prominent objects R Aqr and W Aql. Each shows a characteristic signature of a companion interaction with the stellar wind. For the symbiotic star R Aqr, PACS revealed two perfectly opposing arms that in part reflect the previously observed ring-shaped nebula in the optical. However, from the far-IR there is evidence that the emitting region is elliptical rather than circular. The outline of the wind of W Aql seems to follow a large Archimedean spiral formed by the orbit of the companion but also shows strong indications of an interaction with the interstellar medium. We investigated the nature of the companion of W Aql and found that the magnitude of the orbital period supports the size of the spiral outline.

Organisation(s)
Department of Astrophysics
External organisation(s)
Université Libre de Bruxelles, Technische Universität Graz, Scientific Software Center, Katholieke Universiteit Leuven, Vrije Universiteit Brussel, Royal Observatory of Belgium
Journal
Astronomy & Astrophysics
Volume
549
No. of pages
14
ISSN
0004-6361
DOI
https://doi.org/10.1051/0004-6361/201219259
Publication date
01-2013
Peer reviewed
Yes
Austrian Fields of Science 2012
103003 Astronomy, 103004 Astrophysics
Keywords
ASJC Scopus subject areas
Astronomy and Astrophysics, Space and Planetary Science
Portal url
https://ucrisportal.univie.ac.at/en/publications/d845bfc1-f32e-4158-a685-4bb2d3e6db0b