Solitonic Boson Stars: Numerical solutions beyond the thin-wall approximation

TL;DR

This paper numerically explores solitonic boson stars beyond the thin-wall approximation, analyzing how their properties change with the solitonic potential parameter and examining the validity of the thin-wall approximation.

Contribution

It provides a comprehensive numerical analysis of solitonic boson stars for various potential parameters without relying on the thin-wall approximation, highlighting new behaviors and solution characteristics.

Findings

Behavioral changes in boson star solutions with varying {\sigma}

Assessment of the thin-wall approximation's validity

Different definitions of star radius affect compactness calculations

Abstract

In this paper we present several set of solutions of static and spherically symmetric solitonic boson stars. Each set is characterized by the value of {\sigma} that defines the solitonic potential in the complex scalar field theory. The main features peculiar to this potential occur for small values of {\sigma}, but for which the equations become so stiff as to pose numerical challenges. Without making approximations we build the sets for decreasing {\sigma} values and show how they change their behavior in the parameter space, giving special attention to the region where thin-wall configurations dwell. The validity of the thin-wall approximation is explored as well as the possibility of the solution sets being discontinuous. We investigate five different possible definitions of a radius for boson stars and employ them to calculate the compactness of each solution in order to assess how different the outcomes might be.