HUBBLE-SPACE-TELESCOPE AND GROUND-BASED IMAGING OF THE BIPOLAR PROTOPLANETARY NEBULA M1-92 - EVIDENCE FOR A COLLIMATED OUTFLOW

We present ground-based and Hubble Space Telescope narrowband images o f M1-92. M1-92 is a bipolar proto-planetary nebula currently undergoin g the transition from asymptotic giant branch star to planetary nebula . Previous spectropolarimetry of this object revealed that the line em ission produced in the bipolar lobes is dominated by shock emission, T he goal of the current observations is to determine the morphology of the shock-heated gas in order to better understand the origin of this emission. The ground-based images suggest that the shock emission is c oncentrated in diffuse knots in the bipolar lobes, Our high spatial re solution Wide Field Planetary Camera 2 images demonstrate that the sho ck emission is the result of a collimated outflow that originates near the central star and impacts the bipolar lobes, The outflow axis appe ars to be inclined with respect to the bipolar axis of M1-92, suggesti ng the presence of a precessing or wobbling jet, We discuss these find ings in the context of the current models that seek to explain the pla netary nebula formation process.