The Astrosphere of the Asymptotic Giant Branch Star IRC+10216
Abstract
We have discovered a very extended shock structure (i.e., with a diameter of about 24') surrounding the well-known carbon star IRC+10216 in ultraviolet images taken with the Galaxy Evolution Explorer satellite. We conclude that this structure results from the interaction of IRC+10216's molecular wind with the interstellar medium (ISM), as it moves through the latter. All important structural features expected from theoretical models of such interactions are identified: the termination shock, the astrosheath, the astropause, the bow shock, and an astrotail (with vortices). The extent of the astropause provides new lower limits to the envelope age (69,000 years) and mass (1.4 M sun, for a mass-loss rate of 2 × 10-5 M sun yr-1). From the termination-shock standoff distance, we find that IRC+10216 is moving at a speed of about gsim91 km s-1 (1 cm-3/n ISM)1/2 through the surrounding ISM.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2010
- DOI:
- 10.1088/2041-8205/711/2/L53
- arXiv:
- arXiv:1001.4997
- Bibcode:
- 2010ApJ...711L..53S
- Keywords:
-
- circumstellar matter;
- dust: extinction;
- ISM: structure;
- stars: AGB and post-AGB;
- stars: individual: IRC+10216;
- stars: mass-loss;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 4 pages, 3 color figures