Universal gravitational self-force for a point mass orbiting around a compact star

TL;DR

This paper derives a universal, frequency-dependent self-force formula for a point mass orbiting a compact star, incorporating the star's tidal deformability, aiding gravitational wave modeling for testing gravity theories.

Contribution

It introduces a universal self-force characterization for point masses around compact stars, extending previous black hole results, crucial for gravitational wave analysis.

Findings

Self-force can be expressed via a universal function and the star's tidal deformability.

The model aids in waveform prediction for extreme mass-ratio inspirals around star-like objects.

Supports testing of General Relativity and exotic compact objects with gravitational waves.

Abstract

In this work, we study the gravitational back-reaction (i.e., the "self-force") of a point mass moving around a non-rotating, compact star on a circular orbit. We find that the additional self-force, comparing with the case with a point mass orbiting around a Schwarzschild black hole, can be well characterized by an universal frequency-dependent function multiplied by the (dynamical) tidal deformability of the compact star. This finding provides the foundation for building the waveform model for an extreme mass-ratio inspiral system around a star-like black hole mimicker, which is relevant for testing General Relativity and exotic compact objects with space-borne gravitational wave detectors.