The Optical Form of the Bipolar Preplanetary Nebula IRAS 09371+1212

CCD images of IRAS 09371 + 1212 were taken during two different observing runs at the 1.5-m telescope at La Silla, Chile. The characteristics of the bipolar Frosty Leo Nebula indicate that it is a transitional object belonging to the relatively small class of preplanetary nebulae. It is unique among known objects in two respects: it has the only circumstellar outflow in which crystalline ice dominates the long-wavelength emission spectrum, and it is unique among preplanetary nebulae in having point-reflection-symmetric deviations from axial symmetry. The interpretation offered for this symmetry is that the bipolar outflow is directed by a precessing disk.