Studies in Common Envelope Evolution

首席研究员将对双星共同的包层演化进行数值模拟。人们相信，即使不是全部，大多数短周期双星（周期从小时到天）都是从长周期双星（周期为年）开始的，但随后它们会经历一个共同的包膜阶段，在这个阶段，摩擦减缓了它们的轨道运动，并将它们转变为短周期系统。这项研究是为了研究轨道角动量从恒星转移到一个共同的包层的影响，随后被摩擦过程或引力相互作用抛射出去。这项研究既适用于大质量恒星（双射电脉冲星和x射线双星的前身）的共同包层阶段，也适用于中低质量恒星（灾难性变系统的前身）。目的是确定长轨道周期双星系统转化为短周期系统的参数，以及两颗恒星合并的参数。最终目标是为理解近距离双星系统的性质、起源和演化奠定基础。* * *

Taam 9415423 The Principal Investigator will model numerically the common envelope evolution of binary stars. It is believed that most, if not all, short-period binary stars (periods of hours to days) start out as long-period binaries (periods of years), but then they pass through a common envelope phase during which friction slows their orbital motions and converts them into short-period systems. This research is to investigate the effect of transfer of orbital angular momentum from the stars to a common envelope, which subsequently is ejected by frictional processes or gravitational interactions. The research applies to both the common envelope phases of massive stars (precursors to binary radio pulsars and X-ray binaries) and low-to-intermediate mass stars (precursors to cataclysmic variable systems). The objective is to determine the parameters for which long orbital period binary systems are transformed into short period systems, and the parameters for which two stars merge. The ultimate goal is to lay the foundation for understanding the nature, origin, and evolution of close binary star systems. ***