Spherically-symmetric Perfect Fluid Research Articles

Conformal vector fields of static spherically symmetric perfect fluid space-times in modified teleparallel theory of gravity

In this paper, initially we solve the Einstein field equations (EFEs) for a static spherically (SS) symmetric perfect fluid space-times in the [Formula: see text] gravity with the aid of some algebraic techniques. The extracted solutions are then utilized in order to get conformal vector fields (CVFs). It is important to mention that the adopted techniques enable us to obtain various classes of space-times with viable [Formula: see text] gravity models which already exist in the literature. Excluding all such classes, we find that there exist three cases for which the space-times admit proper CVFs, whereas in rest of the cases, CVFs become KVFs. We have also highlighted some physical implications of our obtained results.

Spherical Symmetric Perfect Fluid Collapse in f(R, T) Gravity

This paper contains the study of spherically symmetric perfect fluid collapse in the frame work of f(R, T) modified theory of gravity. We proceed our work by considering the non-static spherically symmetric background in the interior and static spherically symmetric background in the exterior regions of the star. The junction conditions between exterior and interior regions are presented by matching the exterior and interior regions. The field equations are solved by taking the assumptions that the Ricci scalar as well as the trace of energy-momentum tensor are to be constant, for a particular f(R, T) model. By inserting the solution of the field equations in junction conditions, we evaluate the gravitational mass of the collapsing system. Also, we discuss the apparent horizons and their time formation for different possible cases. It is concluded that the term f(R 0, T 0) behaves as a source of repulsive force and that’s why it slowdowns the collapse of the matter.

Some new similarity solutions of Einstein field equations for spherical symmetric metric of class two

Some spherical symmetric perfect fluid model of embedding class two has been investigated by constructing a fluid sphere of variable pressure and density with property that the pressure and density vanishes at the boundary beyond which Schwarzschild exterior solution prevails. New general solution has been obtained using similarity transformation method; the solution so obtained is new.

Invariant Solutions of Einstein’s Field Equations for Conformally Flat Fluid Spheres of Embedding Class One

In the present paper, conformal spherical symmetric perfect fluid solutions to Einstein’s field equations are obtained by using the invariance of the equations under the Lie group of transformations. All the solutions thus obtained are analyzed physically.

INVARIANT SOLUTIONS OF EINSTEIN FIELD EQUATION FOR NONCONFORMALLY FLAT FLUID SPHERES OF EMBEDDING CLASS ONE

In the present paper, nonconformal spherical symmetric perfect fluid solutions to Einstein field equations are obtained by using the invariance of the equations under the Lie group of transformations and some new solutions of this category are obtained satisfying the reality conditions like ρ ≥ p ≥ 0, ρr< 0, pr< 0 (p and ρ being pressure and energy-density respectively) in the region 0 < r < a. Such fluids do not represent isolated fluid spheres as pressure free interface is not possible for nonconformally perfect fluids of class one.

Gravity, gauge theories and geometric algebra

A new gauge theory of gravity is presented. The theory is constructed in a flat background spacetime and employs gauge fields to ensure that all relations between physical quantities are independent of the positions and orientations of the matter fields. In this manner all properties of the background spacetime are removed from physics, and what remains are a set of `intrinsic' relations between physical fields. The properties of the gravitational gauge fields are derived from both classical and quantum viewpoints. Field equations are then derived from an action principle, and consistency with the minimal coupling procedure selects an action that is unique up to the possible inclusion of a cosmological constant. This in turn singles out a unique form of spin-torsion interaction. A new method for solving the field equations is outlined and applied to the case of a time-dependent, spherically-symmetric perfect fluid. A gauge is found which reduces the physics to a set of essentially Newtonian equations. These equations are then applied to the study of cosmology, and to the formation and properties of black holes. The existence of global solutions enables one to discuss the properties of field lines inside the horizon due to a point charge held outside it. The Dirac equation is studied in a black hole background and provides a quick derivation of the Hawking temperature.

Non-static conformally flat spherically symmetric perfect fluid distribution in Einstein-Cartan theory

In this paper we have obtained general solution representing conformally-flat, non-static spherically-symmetric perfect fluid distribution in Einstein-Cartan theory. In particular, the solution has been also discussed in co-moving coordinates. The explicit expressions for pressure, density, expansion, rotation, shear and non-vanishing components of flow vector have also been found.

General exact solutions of Einstein equations for static perfect fluids with spherical symmetry

The gravitational field equations for a spherical symmetric perfect fluid are completely solved. The general analytical solution obtained depends on an arbitrary function of the radial coordinate. As illustrations of the proposed procedure the exterior and interior Schwarzschild solutions are regained.

A static conformally flat cosmological model in Lyra's manifold

A static conformally flat spherically-symmetric perfect fluid cosmological model based on Lyra's modified Riemannian geometry is proposed. Some properties of the model are discussed.

Non-static fluid spheres in general relativity

A few years ago, Banerjee and Banerji had given a class of exact interior solutions for a spherically-symmetric perfect fluid distributions with inhomogeneous density and pressure. This class serves as a simple model for gravitational collapse with inhomogeneous matter and, therefore, may be of an essential astrophysical importance. It is proved that these solutions are, in fact, identical to the Faulkes earlier solutions.