Studies in Common Envelope Evolution

最近钱德拉和XMM牛顿观测点X射线源人口在银河系和外部星系导致了兴趣的复苏密切相互作用的双系统的演化与紧凑的组件。 观测到的这些系统的质量和轨道周期很难理解，需要大量的质量和角动量损失。 促进这些损失的一个演化通道涉及角动量和能量从双星轨道转移到一个共同的包层，随后被抛出，本项目将研究双星演化的这一所谓的共同包层阶段。 将特别注意包含白色矮致密星的激变变双星系统的形成，以及包含中子星星和黑洞成分的中低质量X射线双星。 本研究的主要目标是在参数空间中划分出双星系统的区域，在这些区域中，双星系统从长轨道周期的双星系统转变为短轨道周期的双星系统，作为合并成单个快速旋转物体的系统的后公共包络幸存者，这些研究将涉及多维流体动力学过程的处理，并且需要高分辨率的三维数值模拟。 为了进行这些模拟，一个自适应的，并行的模拟代码，已特别修改，以处理共同的包络问题将被采用。 这些研究将最终为理解包含致密天体的密近双星系统的形成和演化提供基础。这些项目的影响预计将在当代天体物理学的广泛领域中感受到，包括X射线天文学、引力理论、超新星理论和灾变变星星星研究。 此外，它将有助于科学人力资源的培训和教育，因为高效使用高性能并行计算架构所涉及的数值技术和方法，以及解决这些问题所需的数据管理技能，在这里重点关注的特定领域之外有许多应用。 结果将在芝加哥的阿德勒天文馆天文博物馆向公众展示。 目标是向公众展示可视化在科学发现中的重要性，并传达这些工具可以成为学习科学思想的有效手段。 研究结果也将被纳入西北大学物理和天文学系提供的入门和高级课程。

Recent Chandra and XMM Newton observations of the point X-ray source population in the Milky Way and external galaxies have led to a resurgence of interest in the evolution of close interacting binary systems with compact components. The observed masses and orbital periods for these systems are difficult to understand and require significant loss of both mass and angular momentum. An evolutionary channel which facilitates these losses involves the transfer of angular momentum and energy from the binary orbit to a common envelope which is subsequently ejected.This so-called common envelope phase of binary evolution will be investigated in this project. Particular attention will be focused on the formation of cataclysmic variable binary systems containing white dwarf compact stars as well as on intermediate and low mass X-ray binaries containing neutron star and black hole components. The primary goal of this research is to delineate the regions in parameter space separating progenitor systems in which the binary is transformed from one at long orbital periods to one at short orbital periods as a post common envelope survivor from systems which merge into a single rapidly rotating object.These studies will involve the treatment of multi-dimensional hydrodynamical processes and require high resolution three dimensional numerical simulations. To carry out these simulations, an adaptive, parallel simulation code that has been especially modified to treat the common envelope problem will be employed. The research will ultimately provide a foundation upon which the formation and evolution of close binary systems containing compact objects can be understood.The impact of these projects is expected to be felt across a broad spectrum of contemporary astrophysics including X-ray astronomy, gravitational theory, supernova theory, and cataclysmic variable star research. In addition, it will aid in the training and education of human resources in science since the numerical techniques and methodologies involved in the efficient use of high performance parallel computing architectures and the data management skills required for the solution of these problems have many applications outside of the specific areas focused upon here. The results will be visualized for the general public at the Adler Planetarium & Astronomy Museum in Chicago. The goal will be to show to the public the importance of visualization in scientific discovery for research as well to convey that such tools can be effective means for learning scientific ideas. The results will also be incorporated into both introductory and advanced courses offered by the Department of Physics and Astronomy at Northwestern University.