ABSTRACT. Using the partially completed Submillimeter Array with five antennas, we have observed the CO J = 2-1 and 3-2 emission from the envelope surrounding the carbon star V Hya. The high angular resolution (2''-4'') maps show that V Hya is powering a bipolar molecular jet with an extreme velocity of 70-185 km s^-1. The axis of this high-velocity jet is perpendicular to the major axis of the flattened disklike envelope, which is expanding with a velocity of ~16 km s^-1. There is a third kinematic component, a medium-velocity wind with a deprojected velocity of 40-120 km s^-1 moving along the disk plane. Both the high-velocity jet and the medium-velocity wind have a dynamical timescale of a few hundred years. The flattened structure and the collimated jet observed in V Hya suggest that the formation of asymmetrical structure proceeds while the central star is still in the asymptotic giant branch phase.

Subject headings: ISM: individual (V Hydrae); ISM: jets and outflows; ISM: molecules; stars: AGB and post-AGB

Print publication: Issue 1 (2004 November 20)
Received 2004 May 1, accepted for publication 2004 July 14
Published 2004 October 28