On anisotropic two-fluid stellar objects in General Relativity

TL;DR

This paper develops a covariant framework for modeling static, spherically symmetric stellar objects with two anisotropic fluids in General Relativity, deriving new solutions and extending known theorems from single-fluid cases.

Contribution

It introduces a covariant semi-tetrad approach for two-fluid anisotropic stars and extends generating theorems to this more complex scenario.

Findings

Derived new exact solutions for two-fluid anisotropic stars.

Extended generating theorems from single-fluid to two-fluid models.

Presented covariant form of TOV equations for anisotropic pressures.

Abstract

We apply the 1+1+2 covariant semi-tetrad approach to describe a general static and spherically symmetric relativistic stellar object which contains two fluids with anisotropic pressure. The corresponding Tolman-Oppenheimer-Volkoff equations are then obtained in covariant form for the anisotropic case. These equations are used to obtain new exact solutions using direct resolution and reconstruction techniques. Finally, we show that three of the generating theorems known for the single fluid case can also be used to obtain two-fluid solutions from single fluid ones.