年轻四合星系统中的碎裂与潮汐锁定

中文摘要 AI 辅助

年轻四合星系统为研究不同层级碎裂之间的联系提供了极为简洁的场景。受少数年轻系统中反复出现的对称构型的启发，我们提出了一个理论框架，该框架认为这类构型是在快速坍缩过程中自然形成的。旋转碎裂后发生的次级碎裂可产生一个宽双星系统中的两个质量相当的子天体，每个子天体又进一步碎裂为一个质量不等的密近双星系统。潮汐力与吸积驱动的剪切力相结合，可建立起一种偏好的相位关系：在每个密近双星系统中，质量较小的子天体位于质量较大的子天体的内侧前方。在后续的捕获过程中，这种相位关系可能会发生偏移，使质量较小的子天体位于内侧后方。相干的快速吸积流的不对称分配还可能使碎裂天体的自转轴发生倾斜，为自转轴错位提供了一种可能的起源，而无需初始存在不相干的大尺度流。因此，所提出的机制为年轻四合星构型中的特征相位关系以及星团内随机自旋取向提供了一种可能的物理起源。

英文摘要

Young quadruple systems provide a particularly simple setting in which the connection between successive levels of fragmentation can be studied. Motivated by the recurring symmetric configurations observed in a small number of young systems, we propose a theoretical framework in which such configurations arise naturally during rapid collapse. Rotational fragmentation followed by secondary fragmentation can produce two comparable-mass components of a wide pair, each of which further fragments into an unequal-mass close pair. The combination of tidal forces and accretion-driven shear can then establish a preferred phase relation, with the lower-mass component located on the inner, preceding side of the higher-mass component in each close pair. During subsequent capture, this phase relation can shift, placing the lower-mass component on the inner, trailing side. Asymmetric partitioning of a coherent, rapidly accreting flow can also tilt the spin axes of the fragments, providing a possible origin for spin misalignments without requiring an initially incoherent large-scale flow. The proposed mechanism therefore provides a possible physical origin for the characteristic phase relations in young quadruple configurations and for stochastic spin orientations within star clusters.

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