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Session 46 - Variable Stars - Late Type.
Display session, Thursday, January 08
Exhibit Hall,

[46.04] HST and Infrared Images of the Circumstellar Environment of the Cool Hypergiant IRC+10420

R. M. Humphreys, N. Smith, K. Davidson, T. J. Jones, R. D. Gehrz, C. G. Mason (U. Minnesota), T. L. Hayward, J. R. Houck (Cornell Univ.), J. Krautter (Landessternwarte, Heidelberg, Germany)

WE present HST WFPC2 and groundbased infrared images of the very evolved, luminous OH/IR star IRC+10420. The HST optical images reveal an amazingly complex environment; one with one or more distant reflection shells probably ejected during the stars's previous red supergiant stage plus numerous features within two arcsec of the star including condensations arrayed in jet-like structures, rays and an intriguing group of small nearly spherical shells or arcs apparently at the 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 structure.

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.

Program listing for Thursday