Discrete Orbit Effect Lengthens Merger Times for Inspiraling Binary Black Holes

TL;DR

This paper investigates how the discrete orbit effect, especially in highly eccentric black hole binaries, can significantly extend merger times compared to traditional adiabatic calculations.

Contribution

It introduces a correction to Peters' formula accounting for non-adiabatic effects in highly eccentric inspiraling black hole binaries.

Findings

Merger times can be substantially longer than adiabatic estimates.

Discrepancies are most significant for highly eccentric orbits.

Non-adiabatic effects are crucial for accurate merger time predictions.

Abstract

The inspiral merger time for two black holes captured into a nonrelativistic bound orbit by gravitational radiation emission has been often calculated by a formula of Peters that assumes the adiabatic approximation that the changes per orbit are small. However, initially this is not true for the semimajor axis and period of most of the initially highly eccentric orbits, which change significantly during closest approach and much less elsewhere along the orbit. This effect can make the merger time much longer (using other formulas from Peters that do not assume the adiabatic approximation) than that calculated by the adiabatic formula of Peters.