Compact boson stars in K field theories

TL;DR

This paper demonstrates the existence of novel compact boson star solutions in a scalar field theory with non-standard kinetic terms, including both ball-like and shell-like configurations with unique singularities.

Contribution

It introduces the concept of compact boson stars with non-standard kinetic terms, revealing new types of solutions with singularities and horizons in scalar field gravity models.

Findings

Existence of compact boson star solutions with non-standard kinetic terms

Identification of two types: compact balls and shells

Shell solutions exhibit horizon-like singularities

Abstract

We study a scalar field theory with a non-standard kinetic term minimally coupled to gravity. We establish the existence of compact boson stars, that is, static solutions with compact support of the full system with self-gravitation taken into account. Concretely, there exist two types of solutions, namely compact balls on the one hand, and compact shells on the other hand. The compact balls have a naked singularity at the center. The inner boundary of the compact shells is singular, as well, but it is, at the same time, a Killing horizon. These singular, compact shells therefore resemble black holes.