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T.A. Kuchar, S.J. Carey (BC), S.D. Price (AFRL/VSBC)
A number of Galactic Wolf-Rayet stars show multiple shells of swept-up material surrounding the central stars. These shells are thought to result from various evolutionary phases of the progenitor stars as well as strong stellar winds from Wolf-Rayet stars themselves. IRAS has detected large (> 20') shells around several Wolf-Rayet stars, which are thought to be caused by wind-blown bubbles from the O star progenitor phase. However, the resolution limitations of IRAS precludes the detecting of smaller shells which may have formed during the post O star phases. The Midcourse Space Experiment (MSX) Galactic Plane Survey provides sensitive, high resolution (~18''), mid-IR (6-26 \mum) data capable of resolving these smaller structures. We present images of several Wolf-Rayet stars with large IRAS shells and the evidence for these smaller shells. These smaller shells are conjectured to be caused by ejecta or stellar winds from the Wolf-Rayet stars. Their detection will provide data on the duration of these phases and provide limits on the time scales of the evolutionary phases of these high mass stars.