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B.D. Moore, J.J. Hester, P.A. Scowen (Arizona State University), D.K. Walter (South Carolina State University), R.J. Dufour, P.M. Hartigan, B. Buckalew (Rice University)
Wind-blown bubbles are formed by the interaction of stellar ionizing radiation and winds on the circumstellar material. The ram pressure of the confined wind sweeps up the ambient enivronment into a shell made visible by virtue of its ionization state, maintained by shock-heating and the UV flux of the star. Depending on the mass-loss history of the central star, this material can composed of material processed by the central star, material evaporated from a surrounding HII region, or both.
We analyze recent narrow-band WFPC2 images of NGC 7635, the nebula formed by the wind of the central star BD +60 2522. The morphology of the nebula is described in another poster at this meeting (Walter et al.). Our work focuses on the modeling of the nearby ionized knots utilizing the high spatial resolution afforded by the HST images to construct photoionization models of the region. We also discuss the material comprising the shell, presumed to be comprised solely of the material photoevaporated into the surrounding HII region cavity. We compare these results with ground-based spectroscopy of positions within the image using traditional methods of nebular analysis.
Acknowledgements: This work was supported by STScI grant G0075150396A and NASA/JPL contract 959329-012 at Arizona State University.