发表机构
Technion - Israel Institute of Technology（以色列理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文论证共同包层演化结果因巨星脉动与对流导致的吸积盘和喷流随机性而高度随机，单个系统难以预测，但群体研究仍可用效率参数。
AI 中文摘要
我论证了冷巨星与主序伴星共同包层演化（CEE）中存在显著的随机行为，以至于几乎不可能根据恒星的平均属性和初始轨道来预测单个双星系统的确切CEE结果。我从后CEE行星状星云的两个观测特性出发：许多具有喷流状形态，且形态多样。前者表明标准CEE模型应包含喷流，后者显示CEE具有多种演化路径；例如，喷流可以在主CEE阶段之前、期间和/或之后发射。我展示了主序伴星进入CEE时吸积盘的性质对巨星的脉动和对流敏感且随机地依赖。脉动和巨星包层对流随机决定了包层内吸积盘的演化。吸积盘性质的随机性意味着喷流功率也是随机的。鉴于喷流在CEE结果中起重要作用，我得出结论CEE结果是随机的。我认为CEE效率参数α(CE)对单个系统意义不大，尽管它在群体合成和其他大规模群体研究中仍有意义。
英文摘要
I argue for significant stochastic behavior in the common envelope evolution (CEE) of cool giants and main-sequence companions to the degree that it is almost impossible to know the exact CEE outcome of an individual binary system from the average properties of the stars and their initial orbit. I start with two observational properties of post-CEE planetary nebulae: many have jet-shaped morphologies, and they show a wide variety of morphologies. The first suggests that the standard CEE model should include jets, and the second shows that the CEE has a wide variety of evolutionary routes; for example, jets can be launched before, during, and/or after the main CEE phase. I show that the properties of the disk with which the main-sequence companion enters the CEE depend sensitively and stochastically on the pulsations and convection of the giant star. Pulsations and giant-envelope convection stochastically determine the evolution of the accretion disk inside the envelope. The stochastic nature of the accretion disk properties implies that jet power is also stochastic. Adopting the view that jets play a major role in CEE outcomes, I conclude that the CEE outcome is stochastic. I conclude that the CEE efficiency parameter alpha(CE) has little merit for individual systems, although it still has meaning in population synthesis and other studies of large populations.
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