http://arxiv.org/abs/2209.08487
We revisit the dynamical stability of hierarchical triple systems using direct $N$-body simulations. While there exist several proposals for the triple stability condition, our systematic and long-term numerical integrations reveal that the transition from unstable to stable triples is not abrupt, but rather gradual in general. Thus, the stability “boundary” cannot be defined in an unambiguous fashion, since it is sensitive to the choice of the assumed integration time, in particular for those triples with large mutual inclinations $i_\mathrm{mut}$ between the inner and outer orbits. We show, instead, the distribution of the disruption timescales of triples for different orbital configurations, with particular attention to their $i_\mathrm{mut}$ dependence. We find that a fraction of “unstable” triples remain bound for a long timescale in inclined triples, and thus the stability can be defined only when its disruption timescale is specified. The behavior of stable-unstable transition is very sensitive to the mutual inclination, and we discuss how the stability dependence on $i_\mathrm{mut}$ is explained in terms of the von Zeipel-Kozai-Lidov oscillations.
T. Hayashi, A. Trani and Y. Suto
Tue, 20 Sep 22
51/81
Comments: 11 pages, 3 figures. Submitted to ApJ. Comments welcome
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