Hubble Space Telescope V-band imaging of the bipolar Proto-planetary nebula Iras 17150-3224

摘要

We report Hubble Space Telescope Wide Field Planetary Camera 2 imaging of the bipolar proto-planetary nebula IRAS 17150-3224. We find a series of concentric arcs superposed on the two reflection nebular lobes, similar to those observed in AFGL 2688. This suggests that periodic mass-loss enhancement is a common phenomenon in the asymptotic giant branch (AGB) phase. The near circular shape of the arcs suggests that mass loss is spherically symmetric during the AGB phase and that the bipolar morphology develops only after the end of the AGB phase. The possible evolution in morphology from proto-planetary nebulae to planetary nebulae is discussed.