THE ONSET OF AXIAL SYMMETRY IN PROTOPLANETARY NEBULAE

We have obtained resolved IR images, at wavelengths from 1.2 mu m to 1 2.5 mu m, of a small sample of protoplanetary nebulae. The results sug gest that all PPNe are axially, not spherically, symmetric, that spher ical symmetry ends at the tip of the AGB, and that AGB evolution termi nates with a burst of remarkably rapid, equatorially concentrated mass -loss.