Volume 570, October 2014
|Number of page(s)||6|
|Published online||03 November 2014|
The wonderful complexity of the Mira AB system⋆
1 Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
2 South African Astronomical Observatory, PO box 9, 7935 Observatory, South Africa
3 Dept. of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
4 Department of Physics & Astronomy, Vanderbilt University, Nashville, TN, USA
5 Univ. Bordeaux, LAB, UMR 5804, 33270 Floirac, France
6 ESO, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
7 Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles, CP 226, Boulevard du Triomphe, 1050 Brussels, Belgium
8 Dept. of Astrophysics, Univ. of Vienna, Türkenschanzstr. 17, 1180 Vienna, Austria
9 Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan, 200D, 3001 Leuven, Belgium
10 Laboratoire Lagrange, UMR 7293, Univ. Nice Sophia-Antipolis, CNRS, Observatoire de la Côte d’Azur, 06300 Nice, France
11 Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
12 Centro de Radioastronomía y Astrofísica, Univ. Nacional Autónoma de Mexico, PO Box 3-72, 58090 Morelia, Mexico
Received: 18 September 2014
Accepted: 3 October 2014
We have mapped the 12CO(3–2) line emission around the Mira AB system at 0.̋5 resolution using the Atacama Large Millimeter/submillimeter Array (ALMA). The CO map shows amazing complexity. The circumstellar gas has been shaped by different dynamical actors during the evolution of the system, and several morphological components can be identified. The companion is marginally resolved in continuum emission and is currently at 0.̋487 ± 0.̋006 separation. In the main line component, centered on the stellar velocity, spiral arcs around Mira A are found. The spiral appears to be relatively flat and oriented in the orbital plane. An accretion wake behind the companion is clearly visible, and the projected arc separation is about 5′′. In the blue wing of the line emission, offset from the main line, several large (~5–10′′) opposing arcs are found. We tentatively suggest that this structure is created by the wind of Mira B blowing a bubble in the expanding envelope of Mira A.
Key words: stars: AGB and post-AGB / binaries: symbiotic / circumstellar matter / submillimeter: stars
Appendix A is available in electronic form at http://www.aanda.org
© ESO, 2014
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