The Formation, Evolution, and Impact of Wind-Driven Nebulae around Massive Stars

University Of Chicago, Chicago IL

Investigators

Abstract

AST-0205175 PI Dwarkadas Hot stars, more massive than about eight solar masses, tend to have strong, high-speed outflows of gaseous material, which can result in the formation of wind-blown nebulae around these stars and also can produce effects on the interstellar medium. Recent observations, which have explored the nature of these nebulae with unprecedented resolution, have revealed a variety of aspherical morphologies, with bipolarity being a common theme. Using the theory of radiatively driven winds and numerical simulations, the formation and evolution of these circumstellar nebulae, and the origins of the bipolar structure, will be investigated. These winds are modulated by physical processes such as stellar rotation, gravity darkening, bistability jumps, magnetic channeling of the outflow, and inhomogeneities in the stellar atmospheres. The effect of these processes, both individually and cumulatively, on the latitudinal variation of the winds, and thereby on the morphology of the surrounding nebulae, will be explored. Furthermore, the impact of this circumstellar medium on the subsequent evolution of the massive star as it ends its life in a supernova explosion will be investigated. The results will be compared to recent and archival data in the optical and X-ray regimes. ***