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Astron. Astrophys. 349, 203-208 (1999)


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Multiple shells in the circumstellar envelope of IRC+10216 *

N. Mauron 1 and P.J. Huggins 2

1 Groupe d'Astrophysique, CNRS and Université de Montpellier, Case 072, Place Bataillon, F-34095 Montpellier Cedex 05, France (mauron@merlin.graal.univ-montp2.fr)
2 Physics Department, New York University, 4 Washington Place, New York, NY 10003, USA

Received 28 April 1999 / Accepted 14 June 1999

Abstract

We report deep B and V-band images of IRC+10216 which reveal its extended circumstellar envelope in dust scattered, ambient Galactic light. The envelope is detected out to [FORMULA] from the central star and its structure records the mass-loss history over the past [FORMULA] 8,000 yr. The envelope is roughly spherically symmetric but is composed of a series of discrete, incomplete, concentric shells. The shells are thin ([FORMULA]-[FORMULA]) and separated by [FORMULA]-20", which corresponds to [FORMULA]-800 yr. The shells suggest that some process modulates the mass-loss of the star on this time scale. The presence of shells also means that models of the extended envelope which have been based on smooth distributions of the circumstellar material need to be re-examined.

Key words: stars: AGB and post-AGB – stars: mass-loss – stars: individual: IRC+10216 – stars: circumstellar matter

* Based on observations made with the Canada France Hawaii Telescope, operated by CNRS, the National Research Center of Canada, and the University of Hawaii, and partly at the Haute Provence Observatory (CNRS).

Send offprint requests to: N. Mauron

© European Southern Observatory (ESO) 1999

Online publication: August 25, 1999

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