The circumstellar molecular envelope of HD 101584
Received 18 January 1999 / Accepted 16 April 1999
CO radio line observations reveal a molecular gas envelope around the peculiar star HD101584 with characteristics very similar to those of wellknown young post-AGB objects. We estimate that there is at least 0.1 of molecular gas, very likely remnant gas from a former AGB-envelope. This gas has been efficiently accelerated to very high velocities (50, and a significant fraction to 100). There is evidence for an expanding disk-like structure seen close to edge-on, and a high-velocity bipolar outflow. In the latter the expansion velocity increases linearly with distance from the star, suggesting either a brief period of ejection or a fast wind interacting with a slower wind. A significant fraction of the high-velocity gas has reached a welldefined terminal velocity. Momentum well above the available radiation momentum has been transferred to the gas. There are also indications of high-density, low-velocity molecular gas, possibly in a disk close to the star. The 12CO/13CO-ratio in the envelope is uncertain, but probably quite low (10). The systemic heliocentric velocity is 502.
Key words: stars: circumstellar matter stars: individual: HD 101584 stars: mass-loss stars: AGB and post-AGB radio lines: stars
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© European Southern Observatory (ESO) 1999
Online publication: June 18, 1999