Ghost stars in general relativity

TL;DR

This paper investigates theoretical 'Ghost stars' with negative energy-density regions that result in zero total mass, presenting exact solutions and discussing potential observational evidence for their existence.

Contribution

It introduces the concept of Ghost stars with negative energy-density regions and provides exact analytical solutions within general relativity.

Findings

Exact solutions for Ghost stars are derived.

Properties of Ghost stars are analyzed.

Discussion on observational prospects is included.

Abstract

We explore an idea put forward many years ago by Zeldovich and Novikov concerning the existence of compact objects endowed with arbitrarily small mass. The energy-density of such objects, which we call ``Ghost stars'', is negative in some regions of the fluid distribution, producing a vanishing total mass. Thus, the interior is matched on the boundary surface to Minkowski space-time. Some exact analytical solutions are exhibited and their properties are analyzed. Observational data that could confirm or dismiss the existence of this kind of stellar object is commented.