HST and infrared images of the circumstellar environment of the cool hypergiant IRC+10420

We present HST WFPC2 and ground-based infrared images of the very evolved, luminous OH/IR star IRC+10420. The HST optical images reveal an amazingly complex environment, with one or more distant reflection shells probably ejected during the star's previous red supergiant stage plus numerous features within two arcseconds of the star including condensations arrayed in jet-like structures, rays, and an intriguing group of small, nearly spherical shell or arcs apparently at ends of some of the jet-like features. In contrast, the lower resolution infrared images show two lobes of emission coincident with some of the optical structures. We propose a nearly pole-on model for IRC+10420 with some bipolar symmetry and with the jet-like features, condensations, and arcs produced primarily in the equatorial region. We also present evidence that the mass loss rate has varied during the past few thousand years with a probable high mass loss event during the last 600 years. (C) 1997 The American Astronomical Society. [S0004-6256(97)04912-1].