Compact Boson Stars

TL;DR

This paper studies compact boson stars formed by a V-shaped scalar potential, analyzing their properties, stability, and behavior near the Schwarzschild limit, revealing a stable branch with maximal mass.

Contribution

It introduces a new class of solutions for boson stars with a V-shaped scalar potential and analyzes their stability and physical properties.

Findings

Mass increases with radius along the stable branch.

Maximum mass and size are comparable to Schwarzschild black holes.

Spiraling behavior appears near the maximal mass point.

Abstract

We consider compact boson stars that arise for a V-shaped scalar field potential. They represent a one parameter family of solutions of the scaled Einstein-signum-Gordon equations. We analyze the physical properties of these solutions and determine their domain of existence. Along their physically relevant branch emerging from the compact Q-ball solution, their mass increases with increasing radius. Empoying arguments from catastrophe theory we argue that this branch is stable, until the maximal value of the mass is reached. There the mass and size are on the order of magnitude of the Schwarzschild limit, and thus the spiralling respectively oscillating behaviour, well-known for compact stars, sets in.