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

质量大于8个太阳质量的矮星往往会有强烈的、高速的气体物质流出，这可能导致这些恒星周围形成风吹的星云，也可能对星际介质产生影响。最近的观测以前所未有的分辨率探索了这些星云的本质，揭示了各种各样的非球面形态，双极性是一个共同的主题。利用辐射驱动风理论和数值模拟，将研究这些星周星云的形成和演化，以及双极结构的起源。这些风是由物理过程调制的，如恒星旋转、重力变暗、双稳性跳跃、流出的磁性通道和恒星大气的不均匀性。这些过程，无论是单独的还是累积的，对风的纬度变化的影响，从而对周围星云的形态，将被探索。此外，这种星周介质对大质量恒星在超新星爆炸中结束生命的后续演化的影响将被研究。结果将与光学和x射线体制下的最新和档案数据进行比较。＊＊＊

AST-0205175PI DwarkadasHot 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. ***