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Astron. Astrophys. 362, 255-262 (2000)


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Strong asymmetries in the neutral envelope of Mira *

CO and K I observations

E. Josselin 1,2, N. Mauron 2, P. Planesas 1 and R. Bachiller 1

1 Observatorio Astronómico Nacional (OAN), IGN, Apartado 1143, 28800 Alcalá de Henares, Spain
2 Groupe d'Astrophysique, CC72, CNRS/U. Montpellier II, Place E. Bataillon, 34095 Montpellier Cedex, France

Received 12 April 2000 / Accepted 4 July 2000

Abstract

We present high-resolution observations of the neutral envelope of o Ceti. The molecular component has been mapped in the CO(2-1) radio line and the atomic component is studied through long-slit spectroscopy of the optical KI line. These observations reveal strong asymmetries in the gas distribution, which can be interpreted as a spherical envelope disrupted by a bipolar outflow.

These data, combined with other observations of this object as well as similar observations of other AGB stars, suggest that asymmetrical mass loss processes occur early during the AGB stage, well before the proto-planetary nebula phase.

Key words: stars: AGB and post-AGB – stars: circumstellar matter – stars: individual: o Ceti

* Based on observations carried out with the IRAM Plateau de Bure Interferometer, the Canada-France-Hawaii Telescope, and at the Haute-Provence Observatory. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).

Send offprint requests to: E. Josselin (josselin@oan.es)

© European Southern Observatory (ESO) 2000

Online publication: October 30, 19100

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