2-12.5 MICRON IMAGING OF IRAS 21282+5050 - THE STRUCTURE OF A YOUNG PLANETARY-NEBULA

We present 3.3, 8.5, 10.0, 11.3, and 12.5 mum narrow-band (DELTAlambda/lambda almost-equal-to 3%-10%) and K-band (2.2 mum) high spatial resolution images of IRAS 21282 + 5050 and a 6 cm flux density measurement. The new infrared images reveal a toroidal dust nebula, 4.5'' x 6'', P.A. 165-degrees, with two prominent emission peaks aligned almost E-W and separated by 1''.7-2''.1; a remarkably similar structure to that observed in NGC 7027. From the 6 cm flux density and the dust nebula size, we derive an electron density of 3.6 x 10(3) cm-3 for the central ionized region. Comparison of these images with a published CO 1-0 map suggests that the structure of this dusty, ionization-bounded planetary nebula may reflect the density inhomogeneities of the progenitor's wind. Only slight spatial differences are discernible between the K-band and 10 mum ''dust'' continuum images and the 3.3, 11.3, and 12.5 mum unidentified infrared (UIR) emission-band images which have been attributed to polycyclic aromatic hydrocarbons (PAHs). This tight spatial correlation suggests that the K-band and 10 mum emission also arises from PAHs.