DISCOVERY OF BIPOLAR OH MASER EMISSION FROM THE HIGH-LATITUDE SUPERGIANT STAR HD-101584

We report the discovery of OH 1667 MHz maser emission from the circumstellar envelope of the F-type supergiant star, HD 101584 (IRAS 11385-5517). The OH spectrum has a total velocity range of 84 km s-1 and shows two unusually broad emission features. Images obtained with the Australia Telescope show that the OH masers are located in a bipolar outflow. Along the bipolar axis there is a strong velocity gradient which we interpret as resulting from an interaction between a hot stellar wind and a remnant circumstellar envelope. The presence of high-velocity, bipolar molecular gas in the circumstellar envelope of HD 101584, together with the optical classification, provides strong evidence that the star is a protoplanetary nebula. High-velocity outflows associated with axisymmetric geometries are likely to be a general phenomenon for stars in this short-lived evolutionary stage.