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 evol ved, luminous OH/IR star IRC+10420. The HST optical images reveal an a mazingly complex environment, with one or more distant reflection shel ls probably ejected during the star's previous red supergiant stage pl us numerous features within two arcseconds of the star including conde nsations arrayed in jet-like structures, rays, and an intriguing group of small, nearly spherical shell or arcs apparently at ends of some o f the jet-like features. In contrast, the lower resolution infrared im ages show two lobes of emission coincident with some of the optical st ructures. We propose a nearly pole-on model for IRC+10420 with some bi polar 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) 1 997 The American Astronomical Society. [S0004-6256(97)04912-1].