Studies in Common Envelope Evolution

当代恒星演化理论的一个突出前沿是被称为“共同包层期”的双星演化的短暂时期。在这一阶段之前，绕轨道运行的恒星由于其中一颗恒星之间的质量交换而相互吸引得越来越近，然后一颗“红巨星”膨胀，直到两颗恒星合并，成为一颗普通的“恒星”，其中有两个原子核绕轨道运行。据认为，共同的外壳最终会被弹出，再次留下两颗截然不同的恒星。首席研究员（PI）打算在以前NSF支持的关于普通包膜系统起源的工作的基础上，现在计划研究包膜可以被驱逐的机制。他的模型将通过广泛的二维流体动力学模拟，包括包络物质的循环和冷却（氢、氦原子的重组）的影响。该项目有望对低质量x射线双星和紧密轨道中子星和脉冲星的形成提供额外的理解，因此对天文学界的潜在广泛部分感兴趣。

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.