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Astron. Astrophys. 353, L25-L28 (2000)

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Letter to the Editor

Multiple molecular outflows in AFGL 2688

P. Cox 1, R. Lucas 2, P.J. Huggins 3, T. Forveille 4, R. Bachiller 5, S. Guilloteau 2, J.P.  Maillard 6 and A. Omont 6

1 Université de Paris XI, Institut d'Astrophysique Spatiale, Bât. 120, 91405 Orsay, France
2 IRAM, 300 rue de la Piscine, 38406 Saint Martin d'Hères Cedex
3 New York University, Physics Department, 4 Washington Place, New York, NY 10003, USA
4 Observatoire de Grenoble, B.P. 53X, 38041 Grenoble Cedex, France
5 IGN Observatorio Astronómico Nacional, Apt 1143, 28800 Alcalá de Henares, Spain
6 Institut d'Astrophysique de Paris, CNRS, 98bis bd. Arago, 75014 Paris, France

Received 30 July 1999 / Accepted 12 October 1999


We report high resolution ([FORMULA]) imaging of the proto-planetary nebula AFGL 2688 in the CO (J=2-1) line and the continuum at 230 GHz, using the IRAM interferometer. The observations reveal with unprecedented detail the structure and the kinematics of the gas ejected by the star over the past few hundred years. Two distinct, high-velocity outflow directions are detected emerging from a central core of gas which surrounds the star: one is oriented north-south along the optical axis, the other is oriented east-west, close to the equatorial plane. We resolve the north-south and east-west outflows into a striking series of collimated, bipolar outflows. The tips of the outflows in the east-west direction correspond precisely to H2 emission peaks seen in recent HST imaging at 2 µm, providing direct evidence for the impact and likely shaping effects of jets on the nearly spherical AGB molecular envelope. These outflows exemplify the mechanism by which point symmetries are imprinted on the structure of planetary nebulae at early stages of their formation.

Key words: ISM: planetary nebulae: general – ISM: planetary nebulae: individual: AFGL 2688 – ISM: molecules – stars: AGB and post-AGB

Send offprint requests to: P. Cox (cox@ias.fr)

© European Southern Observatory (ESO) 2000

Online publication: January 18, 2000