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Session 47 - Circumstellar Disks & Shells.
Display session, Thursday, January 08
While tremendous progress has been made in understanding the late stages of planetary nebula development, the details of the earliest phases of this metamorphosis are still a subject of debate. A knowledge of the characteristics of the mass loss occurring as a star leaves the asymptotic giant branch (AGB) is crucial to a complete picture of planetary nebula development, because early mass loss influences the evolution of a nebula through its interaction with subsequent stellar winds. In a spectropolarimetric survey of 31 post- AGB stars, we found that the majority of the objects studied possess extended asymmetric scattering envelopes that are unresolved from the ground. In this work, we present HST WFPC2 images of 5 such post-AGB stars. These data reveal the morphology of the ejecta early in the planetary nebula formation process. We compare the morphology of the objects seen in the WFPC2 images with the structure suggested by the polarization data.
Program listing for Thursday