The formation of close binary systems by dynamical interactions and orbital decay
The formation of close binary systems by dynamical interactions and orbital decay
复制标题
通过动力学相互作用和轨道衰变形成紧密的双星系统
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
V. Bromm
中科院分区：
文献类型：
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作者：
M. Bate;I. Bonnell;V. Bromm
我们目前的结果从第一流体动力学星星形成计算证明，密切的二元恒星系统（分离10 Au）不需要直接形成的碎片。相反，高频率的密近双星可以通过不稳定的多系统中的动力学相互作用和最初较宽的双星的轨道衰变相结合而产生。轨道衰变可能是气体吸积和/或双星与其环双星盘相互作用的结果。这三种机制避免了与光学厚气体的碎裂直接形成封闭系统相关的问题。它们还导致了密近双星具有大致相等质量的成分的偏好，因为动力学交换相互作用和具有高比角动量的气体的吸积将质量比推向统一。此外，由于动力学相互作用的重要性，我们发现质量较大的恒星应该有更高频率的近伴星，许多近双星应该有宽伴星。这些性质与观测结果符合得很好。
We present results from the first hydrodynamical star formation calculation to demonstrate that close binary stellar systems (separations 10 au) need not be formed directly by fragmentation. Instead, a high frequency of close binaries can be produced through a combination of dynamical interactions in unstable multiple systems and the orbital decay of initially wider binaries. Orbital decay may occur as a result of gas accretion and/or the interaction of a binary with its circumbinary disc. These three mechanisms avoid the problems associated with the fragmentation of optically thick gas to form close systems directly. They also result in a preference for close binaries to have roughly equal-mass components because dynamical exchange interactions and the accretion of gas with high specific angular momentum drive mass ratios towards unity. Furthermore, because of the importance of dynamical interactions, we find that stars with greater masses ought to have a higher frequency of close companions, and that many close binaries ought to have wide companions. These properties are in good agreement with the results of observational surveys.