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A general formalism recently proposed to study Newtonian polytropes for anisotropic fluids is here extended to the relativistic regime. Thus, it is assumed that a polytropic equation of state is satisfied by, both, the radial and the…

General Relativity and Quantum Cosmology · Physics 2020-07-02 G. Abellan , E. Fuenmayor , E. Contreras , L. Herrera

In this work we evaluate the physical acceptability of relativistic anisotropic spheres modeled by two polytropic equations of state -- with the same newtonian limit -- commonly used to describe compact objects in General Relativity. We…

General Relativity and Quantum Cosmology · Physics 2021-02-02 D. Suárez-Urango , L. A. Núñez , H. Hernández

We present a class of exact solutions of Einstein's gravitational field equations describing spherically symmetric and static anisotropic stellar type configurations. The solutions are obtained by assuming a particular form of the…

General Relativity and Quantum Cosmology · Physics 2017-10-04 T. Harko , M. K. Mak

Interior structures of stellar objects might have small pressure anisotropy due to several reasons, including rotation and the presence of magnetic fields. Here, retaining the approximation of spherical symmetry, we study the possible role…

Solar and Stellar Astrophysics · Physics 2019-11-06 Shaswata Chowdhury , Tapobrata Sarkar

We consider the general situation of a compact relativistic body with anisotropic pressures in the presence of the electromagnetic field. The equation of state for the matter distribution is linear and may be applied to strange stars with…

General Relativity and Quantum Cosmology · Physics 2009-01-16 S. Thirukkanesh , S. D. Maharaj

We present a class of exact solutions of Einstein's gravitational field equations describing spherically symmetric and static anisotropic stellar type configurations. The solutions are obtained by assuming a particular form of the…

General Relativity and Quantum Cosmology · Physics 2009-11-07 M. K. Mak , T. Harko

In this paper we will discuss charged stars with polytropic equation of state, where we will try to derive an equation analogous to the Lane-Emden equation. We will assume that these stars are spherically symmetric, and the electric field…

Astrophysics · Physics 2009-11-10 Rodrigo Picanco , Manuel Malheiro , Subharthi Ray

In this work the influence of the post-Newtonian corrections to the equations of stellar structure is analysed. The post-Newtonian Lane-Emden equation follows from the corresponding momentum density balance equation. From a polytropic…

General Relativity and Quantum Cosmology · Physics 2022-11-21 Gilberto Medeiros Kremer

The masses and radii of strongly magnetized anisotropic deformed white dwarf stars are investigated using the stellar structure equations in the parameterized $\gamma$-metric formalism. The Equation of State (EoS) of a completely degenerate…

Solar and Stellar Astrophysics · Physics 2024-02-06 Rajasmita Sahoo , Tambe Pranjal Anant , Somnath Mukhopadhyay

We examine the Chandrasekhar limit for white dwarfs in $f(R)$ gravity, with a simple polytropic equation of state describing stellar matter. We use the most popular $f(R)$ gravity model, namely the $f(R)=R+\alpha R^2$ gravity, and calculate…

General Relativity and Quantum Cosmology · Physics 2022-12-21 Artyom V. Astashenok , Sergey D. Odintsov , Vasilis K. Oikonomou

The cosmic neutrino background anisotropy is calculated for massive neutrino states by solving the full Boltzmann equation. The effect of weak gravitational lensing, including the Limber approximation, is also derived for massive particles,…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Steen Hannestad , Jacob Brandbyge

A new class of solutions describing analytical solutions for compact stellar structures has been developed within the tenets of General Relativity. Considering the inherent anisotropy in compact stars, a stable and causal model for…

General Relativity and Quantum Cosmology · Physics 2021-10-14 Jay Solanki , Bhashin Thakore

Static solutions of white dwarfs with spherical symmetry and local anisotropy are studied in the post-Newtonian approximation. It is argued that the condition for equilibrium must be that the total energy is a minimum for given baryon…

General Relativity and Quantum Cosmology · Physics 2009-10-30 E. S. Corchero

In this work, we study self-gravitating objects that obey a polytropic equation of state in hyperbolic symmetry. Specifically, we describe in detail the steps to derive the Lane-Emden equation from the structure equations of the system. To…

General Relativity and Quantum Cosmology · Physics 2025-05-29 M. Carrasco-H , E. Contreras , E. Fuenmayor , P. León

The purpose of this thesis is to obtain more realistic equations of state to describe the matter forming magnetized white dwarfs, and use them to solve its structure equations. The equations of state are determined by considering the weak…

High Energy Astrophysical Phenomena · Physics 2016-01-06 D. Alvear Terrero , D. Manreza Paret , A. Pérez Martínez

In this paper, we found new classes of solutions to the Einstein-Maxwell field equations with matter anisotropic distribution incorporating a particular form of electric field intensity within the framework of general relativity. We use a…

General Relativity and Quantum Cosmology · Physics 2023-10-03 Manuel Malaver , Rajan Iyer

Using the Bower-Liang model, we discuss how pressure anisotropies affect the microscopic and macroscopic properties of hybrid stars. We find that anisotropies affect the maximum mass, central density, and radius of the canonical stars.…

High Energy Astrophysical Phenomena · Physics 2024-10-16 Luiz L. Lopes , H. C. Das

It is suggested a metric ansatz to describe local matter in an expanding universe, hence interpolating between the Schwarzschild metric at small spatial scales and the FLRW metric at large spatial scales. This is acomplished maintaining…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-21 P. Castelo Ferreira

We present a detailed analysis of a general relativistic static spherical symmetric distribution in which both the radial and tangential pressures follow a master polytropic equation of state that generalizes the standard treatment and…

General Relativity and Quantum Cosmology · Physics 2023-03-09 P. León , E. Fuenmayor , E. Contreras

Pressure isotropy, i.e., equality between radial and tangential pressure, is often assumed when studying neutron stars. However, mechanisms such as pion/kaon condensation, magnetic fields, and dark matter clustering can lead to pressure…

High Energy Astrophysical Phenomena · Physics 2026-03-16 Peter T. H. Pang , Stephanie M. Brown , Thibeau Wouters , Chris Van Den Broeck