Herschel’s view into Mira’s head

• Published in: Astronomy and astrophysics (Berlin) Vol. 531; p. L4
• Main Authors: Mayer, A., Jorissen, A., Kerschbaum, F., Mohamed, S., Van Eck, S., Ottensamer, R., Blommaert, J. A. D. L., Decin, L., Groenewegen, M. A. T., Posch, Th, Vandenbussche, B., Waelkens, Ch
• Format: Journal Article
• Language: English
• Published: Les Ulis EDP Sciences 01.07.2011
• Subjects: Astronomy; binaries: general; Earth, ocean, space; Exact sciences and technology; infrared: stars; ISM: general; stars: AGB and post-AGB; stars: mass-loss; O stars; Velocity space; Intensity; infrared: stars; Mass loss; stars: AGB and post-AGB; Bipolar flow; Alignment; Stellar mass; Filaments; stars: mass-loss; binaries: general; ISM: general; Mira stars; Asymptotic giant branch; Infrared star; S stars
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361/201117203

Herschel’s PACS instrument observed the environment of the binary system Mira Ceti in the 70 and 160 μm bands. These images reveal bright structures shaped as five broken arcs and fainter filaments in the ejected material of Mira’s primary star, the famous AGB star o Ceti. The overall shape of the IR emission around Mira deviates significantly from the expected alignment with Mira’s exceptionally high space velocity. The observed broken arcs are neither connected to each other nor are they of a circular shape; they stretch over angular ranges of 80 to 100 degrees. By comparing Herschel and GALEX data, we found evidence for the disruption of the IR arcs by the fast outflow visible in both Hα and the far UV. Radial intensity profiles are derived, which place the arcs at distances of 6–85″ (550−8000 AU) from the binary. Mira’s IR environment appears to be shaped by the complex interaction of Mira’s wind with its companion, the bipolar jet, and the ISM.