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Session 44 - Circumstellar Material.
Display session, Tuesday, January 16
North Banquet Hall, Convention Center

[44.08] IRAS Observations of Nebulae Around Wolf-Rayet Stars

A. P. Marston (Drake U.), D. R. Yocum (NOAO)

We present IRAS Skyflux and HIRES images of the environments of galactic Wolf-Rayet stars. These form part of a complete sample of all galactic Wolf-Rayet stars observed by IRAS, a total of some 160 stars. The intent of this survey is to obtain information on the large bubbles expected from the early O star phase of Wolf-Rayet stars, as well as providing estimates of the dust and gas masses of any ejecta shells occuring after the O star phase, and seen interior to the O star bubbles. So far, a total of more than 40 probable or suspected shells of > 0.5 degrees in diameter have been observed in our data, which may be associated with Wolf-Rayet stars. We indicate how information from this work may be used to pin down parts of the evolutionary sequence of Wolf-Rayet stars, including estimates of the time periods for which both WN and WC subtypes spend in an O star and heavy wind stage. This work is supported in part by a NASA ADP grant, NAG 5-2999.

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