Studies in Common Envelope Evolution

当代恒星演化理论的一个突出前沿是双星演化的短暂阶段，即所谓的“共同包络阶段”。在此阶段之前，轨道运行的恒星作为其中的一颗，通过它们之间的质量交换而被吸引得越来越近，然后一个“红巨星”膨胀，直到两颗恒星合并，成为一颗共同的“恒星”，在其中两个原子核围绕轨道运行。人们认为，共同的包层最终会被抛出，再次留下两颗截然不同的恒星。首席调查员(PI)打算在以前由国家科学基金会支持的关于共同信封系统起源的工作的基础上再接再厉，现在计划研究可以驱逐信封的机制(S)。他的模型将通过广泛的二维流体动力学模拟，包括包层物质的循环和冷却(氢、氦原子的复合)的影响。该项目预计将对低质量X射线双星和近轨道中子星和脉冲星的形成有更多的了解，因此可能会引起天文学界的广泛关注。

One of the outstanding frontiers of contemporary stellar evolution theory is that brief period of binary star evolution known as the "common envelope phase." Prior to this phase, orbiting stars are attracted closer and closer to one another by the exchange of mass between them as one of them, then a "red giant" expands until the two stars coalesce, becoming a common "star" within which two nuclei orbit. It is thought that the common envelope is eventually ejected, leaving behind two distinct stars once again. The Principal Investigator (PI) intends to build on previous NSF- supported work on the origins of common envelope systems and now plans to study the mechanism(s) by which the envelope can be expelled. His models will include effects of circulation and cooling (recombination of H, He atoms) of an envelope matter through extensive two-dimensional hydrodynamic simulations. This project is expected to give additional understanding to the formation of low mass x-ray binaries and closely orbiting neutron stars and pulsars, and is thus of interest to a potentially wide segment of the astronomical community.