An Icy, Bipolar Proto-Planetary Nebula with Knotty Jets: IRAS 22036+5306

Abstract

Using the Hubble Space Telescope's Wide Field Planetary Camera 2, we have discovered that the proto-planetary nebula (PPN) IRAS 22036+5306 (I22036) is an extended (5.7"×1.3") bipolar nebula. A dark, (partial) ringlike band defines the nebular waist region and probably results from a tilted, geometrically thick disk that obscures the central star. Knotty, linear structures are seen in each lobe. Very Large Array A configuration observations of OH maser emission in I22036 show the 1667 MHz emission features aligned in a roughly 1.8" long linear structure along the nebular axis. The source's far-infrared fluxes imply the presence of a massive [~5(D/2 kpc)² M_solar], dusty, cool (T_dust~35-67 K), circumstellar envelope. Strong 3.08 and 11 μm absorption features in the Infrared Space Observatory spectra show the presence of icy silicate grains, which probably reside in the disk's shielded outer regions. A low-resolution optical spectrum indicates an F5 (or earlier) spectral type for the post-asymptotic giant branch (AGB) central star and shows Hα and Hβ emission lines. The elongated and highly structured lobes of I22036 are likely to have been produced as a result of the interaction of a collimated, fast wind (CFW) with the AGB progenitor's dense, slow wind. Highly collimated jetlike components in the CFW have probably operated at some time during the formation of this PPN.