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A new class of solutions describing the composition of compact stars has been proposed, assuming that the fluid distribution inside the star is anisotropic. This is achieved by assuming the appropriate metric potential and then solving…

General Physics · Physics 2020-03-11 D. M. Pandya , B. Thakore , R. Goti , J. P. Rank , S. Shah

We consider spherically symmetric spacetimes sourced by a fluid with pressure anisotropy in the radial direction. We use gauge-invariant perturbation theory to study the stability of this class of spacetimes under axial perturbations. We…

General Relativity and Quantum Cosmology · Physics 2014-07-23 Bhavesh Khamesra , V Suneeta

This article presents a new model for anisotropic compact stars that are confined to physical dark matter in the background of $f(T)$ teleparallel gravity. The model is based on the equation of state (EoS) of the bag model type and the…

General Relativity and Quantum Cosmology · Physics 2024-08-06 Samprity Das , Prabir Rudra , Surajit Chattopadhyay

Anisotropic stresses are ubiquitous in nature, but their modeling in General Relativity is poorly understood and frame dependent. We introduce the first study on the dynamical properties of anisotropic self-gravitating fluids in a covariant…

General Relativity and Quantum Cosmology · Physics 2019-06-05 Guilherme Raposo , Paolo Pani , Miguel Bezares , Carlos Palenzuela , Vitor Cardoso

The accelerated expansion of the Universe can be suitably attributed to the existence of the dark energy (DE). On the backdrop of this concept, this paper introduces a novel, anisotropic compact star model whose stability and structure are…

General Relativity and Quantum Cosmology · Physics 2025-11-25 Meghanil Sinha , S. Surendra Singh

We consider a gravastar model made of anisotropic dark energy with an infinitely thin spherical shell of a perfect fluid with the equation of state $p = (1-\gamma)\sigma$ with an external de Sitter-Schwarzschild region. It is found that in…

General Relativity and Quantum Cosmology · Physics 2015-03-19 R. Chan , M. F. A. da Silva , P. Senna , J. F. Villas da Rocha

We discuss a model of the universe where dark energy is replaced by electrically-charged extremely-massive dark matter. The cosmological constant has a value of the same order as the mean matter density, consistent with observations, and is…

General Physics · Physics 2026-01-26 Paul H. Frampton

We consider a self-consistent system of Bianchi type-I (BI) gravitational field and a binary mixture of perfect fluid and dark energy. The perfect fluid is taken to be the one obeying the usual equation of state, i.e., $p = \zeta \ve$, with…

General Relativity and Quantum Cosmology · Physics 2015-05-01 Bijan Saha

This paper investigates a spherically symmetric compact relativistic body with isotropic pressure profiles within the framework of general relativity. In order to solve the Einstein's field equations, we have considered the Vaidya-Tikekar…

Astrophysics of Galaxies · Physics 2021-11-29 Jitendra Kumar , Puja Bharti

The main aim of this study is to examine the behaviour of physical parameters of an anisotropic compact star model demonstrating spherical symmetry in F(Q) modified gravity. To evaluate the behaviour and the stability of an anisotropic…

General Relativity and Quantum Cosmology · Physics 2025-05-26 Sat Paul , Jitendra Kumar , S. K. Maurya

In the present paper we obtain an anisotropic analogue of Durgapal-Fuloria (1985) perfect fluid solution. The methodology consists of contraction of anisotropic factor $\Delta$ by the help of both metric potentials $e^{\nu}$ and…

General Relativity and Quantum Cosmology · Physics 2015-06-02 S. K. Maurya , Y. K. Gupta , Saibal Ray , Baiju Dayanandan

In this paper we found a new model for compact star with anisotropic matter distribution considering the new version of Chaplygin fluid equation of state of Errehymy and Daoud (2021). We specify the particular form of the metric potential…

General Relativity and Quantum Cosmology · Physics 2022-04-29 Manuel Malaver , Rajan Iyer

We develop a new model for a spherically symmetric dark matter fluid sphere containing two regions: {\bf (i)} Isotropic inner region with constant density and {\bf (ii)} Anisotropic outer region. We solve the system of field equation by…

General Relativity and Quantum Cosmology · Physics 2020-12-02 Shyam Das , Nayan Sarkar , Monimala Mondal , Farook Rahaman

A variety of observational tests seem to suggest that the universe is anisotropic. This is incompatible with the standard dogma based on adiabatic, rotationally invariant perturbations. We point out that this is a consequence of the…

Astrophysics · Physics 2009-11-11 Richard A. Battye , Adam Moss

By employing modified Chaplygin fluid prescription for the dark energy, we construct slowly rotating isotropic and anisotropic dark energy stars. The slow rotation is incorporated via general relativistic Hartle-Thorne formalism; whereas…

General Relativity and Quantum Cosmology · Physics 2024-07-26 O. P. Jyothilakshmi , Lakshmi J. Naik , V. Sreekanth

In the present paper we have constructed a new relativistic anisotropic compact star model having a spherically symmetric metric of embedding class one. Here we have assumed an arbitrary form of metric function and solved the Einstein…

General Relativity and Quantum Cosmology · Physics 2017-07-26 Piyali Bhar , Ksh. Newton Singh , Tuhina Manna

Dark energy is usually parametrized as a perfect fluid with negative pressure and a certain equation of state. Besides, it is supposed to interact very weakly with the rest of the components of the universe and, as a consequence, there is…

Astrophysics · Physics 2015-05-13 Jose Beltran Jimenez , Antonio L. Maroto

In this paper, we derive some new invariant solutions of dark energy models in cylindrically symmetric space-time. To quantify the deviation of pressure from isotropy, we introduce three different time dependent skewness parameters along…

General Relativity and Quantum Cosmology · Physics 2014-09-10 Anil Kumar Yadav , Ahmad T Ali

We consider ideal fluid and equivalent scalar field dark energy universes where all four known types of finite-time, future singularities occur at some parameter values. It is demonstrated that pressure/energy density of such…

High Energy Physics - Theory · Physics 2015-05-13 Shin'ichi Nojiri , Sergei D. Odintsov

In the present paper we develop an algorithm for all spherically symmetric anisotropic charged fluid distribution. Considering a new source function $\nu(r)$ we find out a set of solutions which is physically well behaved and represent…

General Relativity and Quantum Cosmology · Physics 2017-06-12 S. K. Maurya , Y. K. Gupta , Saibal Ray