Gravitational Waves from Hierarchical Triple Systems with Kozai-Lidov Oscillation

TL;DR

This paper investigates how Kozai-Lidov oscillations in hierarchical triple systems influence gravitational wave signals, revealing observable waveform variations that can be detected by future space interferometers to study such complex systems.

Contribution

It provides the first analysis of gravitational wave features from inner binaries undergoing Kozai-Lidov oscillations in hierarchical triples.

Findings

Waveform variations due to tertiary companion are observable.

Energy spectra show distinct features from isolated binaries.

Future space interferometers can detect these signals in the mHz range.

Abstract

We study gravitational waves from a hierarchical three-body system up to first-order postNewtonian approximation. Under certain conditions, the existence of a nearby third body can cause periodic exchange between eccentricity of an inner binary and relative inclination, known as Kozai-Lidov oscillations. We analyze features of the waveform from the inner binary system undergoing such oscillations. We find that variation caused due to the tertiary companion can be observed in the gravitational waveforms and energy spectra, which should be compared with those from isolated binaries and coplanar three-body system. The detections from future space interferometers will make possible the investigation of the gravitational wave spectrum in mHz range and may fetch signals by sources addressed.