Star Models with Dark Energy

TL;DR

This paper constructs detailed star models with multiple layers, including dark energy components, and analyzes their energy conditions, revealing that dark energy is necessary for static solutions and that mass-to-radius ratios are key constraints.

Contribution

The study introduces multi-layer star models with dark energy and analyzes their energy conditions, highlighting the necessity of dark energy for static configurations.

Findings

Dark energy must be present in at least one region for static solutions.

No upper mass limit exists, only a limit on mass-to-radius ratio.

Energy conditions are satisfied in the constructed models.

Abstract

We have constructed star models consisting of four parts: (i) a homogeneous inner core with anisotropic pressure (ii) an infinitesimal thin shell separating the core and the envelope; (iii) an envelope of inhomogeneous density and isotropic pressure; (iv) an infinitesimal thin shell matching the envelope boundary and the exterior Schwarzschild spacetime. We have analyzed all the energy conditions for the core, envelope and the two thin shells. We have found that, in order to have static solutions, at least one of the regions must be constituted by dark energy. The results show that there is no physical reason to have a superior limit for the mass of these objects but for the ratio of mass and radius.