The Eccentric Kozai-Lidov Effect and Its Applications

TL;DR

This paper discusses the eccentric Kozai-Lidov mechanism, a dynamical process in hierarchical triple systems causing extreme eccentricity and inclination oscillations, with significant implications for astrophysical phenomena like binary mergers.

Contribution

It provides a comprehensive overview of the eccentric Kozai-Lidov effect, highlighting its chaotic behavior, parameter space accessibility, and broad applicability across astrophysical systems.

Findings

Eccentric Kozai-Lidov induces extreme eccentricity and inclination oscillations.

System behavior can be chaotic and highly sensitive to initial conditions.

Applicable to diverse astrophysical scenarios from planetary to supermassive black holes.

Abstract

The hierarchical triple body approximation has useful applications to a variety of systems from planetary and stellar scales to supermassive black holes. In this approximation, the energy of each orbit is separately conserved and therefore the two semi-major axes are constants. On timescales much larger than the orbital periods, the orbits exchange angular momentum which leads to eccentricity and orientation (i.e., inclination) oscillations. The orbits' eccentricity can reach extreme values leading to a nearly radial motion, which can further evolve into short orbit periods and merging binaries. Furthermore, the orbits' mutual inclination may change dramatically from pure prograde to pure retrograde leading to misalignment and a wide range of inclinations. This dynamical behavior is coined as the "eccentric Kozai-Lidov" mechanism. The behavior of such a system is exciting, rich and chaotic in nature. Furthermore, these dynamics are accessible from a large part of the triple body parameter space and can be applied to diverse range of astrophysical settings and used to gain insights to many puzzles.