Stability and Evolution of Interacting Close Binary Stars

相互作用的紧密双星的稳定性和演化

• 批准号: 0406726
• 负责人: Ronald Webbink
• 金额: --
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0406726&HistoricalAwards=false
• 关键词: Stability; Evolution; Interacting; Close; Binary

AST 0406726 PI Webbink Unlike the evolution of single stars, which is to a first approximation a function only of initial mass and chemical composition, the evolution of interacting binary stars involves at minimum four parameters: the masses of each of the two stars, their orbital separation (or period), and chemical composition. The large number of parameters makes it prohibitively expensive to explore every combination possible. Furthermore, theory is not yet able to rigorously quantify many critical physical processes, most especially the extent of mass and angular momentum loss from a binary undergoing mass exchange between components. Statistical models which attempt to reproduce the distributions of observable properties of different kinds of close binary systems (population synthesis models) offer the opportunity for insight to the magnitude of these effects. These models rely upon simple parameterizations of single-star evolution models, combined with a broad, but very incomplete, understanding of how interacting binary stars evolve based on the behavior of the relatively small number of detailed binary evolutionary models in the published literature. The research program here is providing a rigorous general framework for population synthesis models, as well as exploring specific evolutionary problems of widespread interest to researchers in binary star evolution. The work encompasses an array of projects critical to progress in binary evolution theory. Construction of adiabatic and thermal-equilibrium mass loss sequences for stars spanning the entire range of the masses and evolutionary states will define mass transfer time scales appropriate to all classes of interacting binary stars. The evolution of binary stars in physical contact with each other is explored with a simultaneous binary evolution code, magnetic field coupling to binary evolution among the magnetic cataclysmic binaries, and the modeling of wind-fed magnetic cataclysmic variables. Broader Impacts: This work includes a graduate student, now engaged in preparatory work for her Ph.D. dissertation, who will also participate in national and international conferences. Three of the major components of this research involve international collaborations, with researchers in China, Australia, and Germany. The numerical results of the stability study are to be made available in digital form, since it has broad application for all kinds of binary evolution studies. And finally, the proposed studies of donor star variability in cataclysmic variables provide the means to test for long-term stochastic variability among lower-main-sequence stars. This project also maintains and develops binary star databases.

AST 0406726 PI Webbink不同于单星的演化，单星的演化在一级近似下仅是初始质量和化学成分的函数，交互作用双星的演化至少涉及四个参数：两颗恒星中每一颗的质量，它们的轨道间隔（或周期）和化学成分。大量的参数使得探索每一种可能的组合都非常昂贵。此外，理论还不能严格量化许多关键的物理过程，特别是质量和角动量损失的程度，从一个双进行质量交换组件之间。试图再现不同种类的近距离双星系统（人口合成模型）的可观测属性的分布的统计模型提供了洞察这些影响的大小的机会。这些模型依赖于单星演化模型的简单参数化，结合广泛的，但非常不完整的理解，如何相互作用的双星演化的基础上的行为相对较少的详细的双星演化模型在已发表的文献。这里的研究计划提供了一个严格的总体框架人口合成模型，以及探索特定的进化问题的研究人员在二元星星演化的广泛兴趣。这项工作包括一系列对二元进化理论的进展至关重要的项目。建设的绝热和热平衡质量损失序列跨越整个范围的质量和演化状态的恒星将定义质量转移的时间尺度适合于所有类别的相互作用的双星。本文利用同步双星演化程序、磁激变双星中磁场与双星演化的耦合以及风馈磁激变变星的模拟，研究了相互接触的双星演化。更广泛的影响：这项工作包括一名研究生，现在正在为她的博士学位做准备。论文，谁也将参加国家和国际会议。这项研究的三个主要组成部分涉及国际合作，与中国，澳大利亚和德国的研究人员。稳定性研究的数值结果将以数字形式提供，因为它对各种二元演化研究具有广泛的应用。最后，对激变变星中施主星星变率的研究为检验低主序星的长期随机变率提供了手段。该项目还维护和开发二进制星星数据库。