Eccentricity Boost of Stars Around Shrinking Massive Black Hole Binaries

TL;DR

This paper investigates how the Kozai-Lidov mechanism causes stars around shrinking black hole binaries to develop high eccentricities due to a bifurcation pattern influenced by stellar cluster potentials.

Contribution

It introduces a simple geometrical model revealing a bifurcation pattern that leads to eccentricity boosts in stars near shrinking black hole binaries.

Findings

Stars can become highly eccentric due to bifurcation effects.

The transition to high eccentricity occurs abruptly for stars with small initial eccentricities.

The approach can be applied to other astrophysical scenarios involving Kozai-Lidov dynamics.

Abstract

Based on a simple geometrical approach, we analyze the evolution of the Kozai-Lidov mechanism for stars around shrinking massive black hole binaries on circular orbits. We find that, due to a peculiar bifurcation pattern induced by the Newtonian potential of stellar clusters, the orbit of stars could become highly eccentric. This transition occurs abruptly for stars with small initial eccentricities. Our approach would be also useful for studying the Kozai-Lidov mechanism in various astrophysical contexts.