Implementing Tidal and Gravitational Wave Energy Losses in Few-body Codes: A Fast and Easy Drag Force Model

TL;DR

This paper introduces a fast, easy-to-implement drag force model for simulating energy losses due to tides and gravitational waves in chaotic few-body interactions, aiding the study of transient astrophysical phenomena.

Contribution

It provides a novel, computationally efficient drag force approach to incorporate tidal and GW energy losses in few-body simulations, compatible with existing models.

Findings

The drag force model accurately reproduces results from more complex methods.

It significantly reduces computational time for few-body simulations.

The approach is versatile for modeling various energy loss mechanisms.

Abstract

We present a drag force model for evolving chaotic few-body interactions with the inclusion of orbital energy losses, such as tidal dissipation and gravitational wave (GW) emission. The main effect from such losses is the formation of two-body captures, that for compact objects result in GW mergers, and for stars lead to either compact binaries, mergers or disruptions. Studying the inclusion of energy loss terms in few-body interactions is therefore likely to be important for modeling and understanding the variety of transients that soon will be observed by current and upcoming surveys. However, including especially tides in few-body codes has been shown to be technically difficult and computationally heavy, which has lead to very few systematic tidal studies. In this paper we derive a drag force term that can be used to model the effects from tidal, as well as other, energy losses in few-body interactions, if the two-body orbit averaged energy loss is known a priori. This drag force model is very fast to evolve, and gives results in agreement with other approaches, including the impulsive and affine tide approximations.