A Coordinate System for Dynamical Instabilities in Hierarchical Systems in REBOUND

TL;DR

This paper introduces a new coordinate system for studying wide binary systems in the REBOUND N-body simulation package, improving performance and accuracy in regimes where traditional methods struggle.

Contribution

The authors implement and benchmark a novel coordinate system in REBOUND that enhances the simulation of wide binary systems, especially during close encounters.

Findings

Achieves up to 9x speedup over high-precision integrators.

Qualitatively correct results in planet scattering, flybys, and ZLK oscillations.

Performs better than traditional hybrid integrators in challenging regimes.

Abstract

We implement coordinates suitable for studying wide binary systems in TRACE, a hybrid integrator in the widely used open-source N-body integration package REBOUND. This is a regime in which traditional hybrid integrators perform poorly. The coordinate system supports close encounters between any pair of bodies in the system. We describe the implementation of this coordinate system and benchmark its performance against other integrators in the REBOUND ecosystem. In tests of planet-planet scattering, stellar flybys, and ZLK oscillations. TRACE in wide binary coordinates is qualitatively correct when other hybrid methods fail, and in many cases returns statistically similar results to the high-precision IAS15 integrator with up to 9x speedups. We also provide some guidelines for when use of these coordinates are appropriate.