Effects of Rotation and Magnetic Fields on the Winds from Early Type Stars

一段时间以来，天文学家已经探索了磁场、湍流速度场和冷却“耀斑”恒星大气中旋转的相互联系的本质。对于热的、正常丰度的“Be”恒星来说，这是一个更有争议的话题，因为很难测量这些恒星的磁场，因为它们的光谱线被恒星的旋转弄脏了。尽管如此，人们普遍认为，一些物理过程，如辐射压力、旋转、磁场和脉动，可能以一种复杂的方式相互作用，导致这些恒星“间歇性地”喷射物质，也就是说，不时地，而不是以一种平稳的方式，如“风”。首席研究员（PI）和他的同事们建议继续先前的“风压缩盘”模型的工作，以解释一旦喷射开始，以另一种方式，环绕恒星的赤道盘是如何发展并与高纬度地区辐射驱动的风相互作用的。该奖项将资助博士后J. Bjorkman博士三年，并允许他改进他的模型，以便在观测到的极化和光谱特征随时间变化的背景下解释它。这项工作预计将对其他各种类型的恒星产生影响，这些恒星在演化过程中会周期性地喷射出质量，即使是通过其他机制。

For some time astronomers have explored the interconnected nature of magnetic fields, turbulent velocity fields, and rotation in the atmospheres of cool "flare" stars. For hot, normal-abundance "Be" stars this is a more controversial subject because it is difficult to measure magnetic fields in these stars because their spectral lines are smeared by the stars' rotation. Nonetheless, it is generally thought that several physical processes, such as radiation pressure, rotation, magnetic fields, and pulsation, may interact in a complicated way to cause these stars to eject matter "episodically," that is, from time to time rather than in a smooth fashion, such as a "wind." The Principal Investigator (PI) and his colleagues propose to continue previous work on a "wind compressed disk" model to explain how, once the ejection has started by another means, how a circum-stellar equatorial disk develops and interacts with the radiation-driven wind at higher latitudes. This award will support a postdoc-toral fellow, Dr. J. Bjorkman, over three years and will permit him to refine his model to interpret it in the context of observed changes in polarization and spectral characteristics with time. This work is expected to have an impact on a variety of other types of stars that periodically eject mass during their evolutions, even if by other mechanisms.