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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

This paper is devoted to explore some relativistic configurations of stellar objects for static spherically symmetric structures in the context of modified $f(\mathcal{G})$ gravity, by exploiting the Tolman-Kuchowicz spacetime [1,2]. We…

General Relativity and Quantum Cosmology · Physics 2020-01-23 M. Farasat Shamir , Tayyaba Naz

In this work we present a stellar structure model from $f(\mathcal{R})$-gravity point of view capable to describe some classes of stars (White Dwarfs, Brown Dwarfs, Neutron stars, Red Giants and the Sun). This model was based on…

General Relativity and Quantum Cosmology · Physics 2017-08-30 Raíla André , Gilberto M. Kremer

This manuscript examines viability and stability of anisotropic compact objects in the framework of $f(Q,L_m)$ gravity ($Q$ is the non-metricity and $L_m$ is the matter Lagrangian). We assume a particular functional form of this theory to…

General Relativity and Quantum Cosmology · Physics 2026-05-05 M. Sharif , M. Zeeshan Gul , Adeeba Arooj

We study static, spherically symmetric equilibrium configurations in extended theories of gravity (ETG) following the notation introduced by Capozziello et {\it al}. We calculate the differential equations for the stellar structure in such…

General Relativity and Quantum Cosmology · Physics 2016-12-22 Aneta Wojnar , Hermano Velten

We present a new formulation to construct numerically equilibrium configurations of rotating stars in general relativity. Having in mind the application to their quasi static evolutions, we adopt a Lagrangian formulation of our own…

General Relativity and Quantum Cosmology · Physics 2022-04-22 Hirotada Okawa , Kotaro Fujisawa , Nobutoshi Yasutake , Misa Ogata , Yu Yamamoto , Shoichi Yamada

In this work we analyze hydrostatic equilibrium configurations of neutron stars in a non-minimal geometry-matter coupling (GMC) theory of gravity. We begin with the derivation of the hydrostatic equilibrium equations for the $f(R,L) $…

General Relativity and Quantum Cosmology · Physics 2020-05-14 G. A. Carvalho , P. H. R. S. Moraes , S. I. dos Santos , B. S. Gonçalves , M. Malheiro

A gauge-invariant, linear cosmological perturbation theory of an almost homogeneous and isotropic universe with dynamically evolving Newton constant G and cosmological constant $\Lambda$ is presented. The equations governing the evolution…

General Relativity and Quantum Cosmology · Physics 2011-04-22 Adriano Contillo

We study the internal structure of a static and spherically symmetric neutron star in the framework of an in-medium modified chiral soliton model. The Equations of State describing an infinite and asymmetric nuclear matter are obtained…

Nuclear Theory · Physics 2015-09-30 Ulugbek Yakhshiev

We develop the general theory of stars in Saa's model of gravity with propagating torsion and study the basic stationary state of neutron star. Our numerical results show that the torsion force decreases the role of the gravity in the star…

General Relativity and Quantum Cosmology · Physics 2010-11-19 T. Boyadjiev , P. Fiziev , S. Yazadjiev

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

The inner crust of a mature neutron star is composed of an elastic lattice of neutron-rich nuclei penetrated by free neutrons. These neutrons can flow relative to the crust once the star cools below the superfluid transition temperature. In…

General Relativity and Quantum Cosmology · Physics 2019-05-22 N. Andersson , B. Haskell , G. L. Comer , L. Samuelsson

We investigate the dynamical stability of bootstrapped Newtonian stars following homologous adiabatic perturbations, focusing on objects of low or intermediate compactness. The results show that for stars with homogeneous densities these…

General Relativity and Quantum Cosmology · Physics 2024-08-08 Octavian Micu

We study static symmetric solutions in the context of a gravitational theory based on a action-dependent Lagrangian. Such theory has been designed as a setup to implement dissipative effects into the traditional principle of least action.…

General Relativity and Quantum Cosmology · Physics 2019-06-26 Julio C. Fabris , Hermano Velten , Aneta Wojnar

We study the structure of neutron stars in f(R) gravity theories with perturbative constraints. We derive the modified Tolman-Oppenheimer-Volkov equations and solve them for a polytropic equation of state. We investigate the resulting…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Alan Cooney , Simon DeDeo , Dimitrios Psaltis

Taking a novel approach, this paper discuss the structure of compact stars, an important topic in theoretical astrophysics. Adopting the Newtonian gravitation, we solve the hydrostatic equilibrium equation by imposing a simple…

Solar and Stellar Astrophysics · Physics 2014-07-22 Hilario Rodrigues

The paper provides a new framework for the description of linearized adiabatic lagrangian perturbations and stability of differentially rotating newtonian stars. In doing so it overcomes problems in a previous framework by Dyson and Schutz…

Astrophysics · Physics 2014-10-13 Horst R. Beyer

We propose a unimodular version of the Brans-Dicke theory designed with a constrained Lagrangian formulation. The resulting field equations are traceless. The vacuum solutions in the cosmological background reproduce the corresponding…

General Relativity and Quantum Cosmology · Physics 2022-07-28 Alexandre M. R. Almeida , Júlio C. Fabris , Mahamadou Hamani Daouda , Richard Kerner , Hermano Velten , Wiliam S. Hipólito-Ricaldi

The post Newtonian parameter is considered in the Chameleon-Brans-Dicke frame. In the first step, the general form of this parameter and also effective gravitational constant is obtained. An arbitrary function for $f(\Phi)$, which indicates…

General Relativity and Quantum Cosmology · Physics 2014-01-20 Khaled Saaidi , Abolhassan Mohammadi , Haidar Sheikhahmadi

We construct equilibrium configurations for neutron stars using a specific $f(R,T)$ functional form, recently derived through gaussian process applied to measurements of the Hubble parameter. By construction, this functional form serves as…

General Relativity and Quantum Cosmology · Physics 2024-11-15 J. T. Quartuccio , P. H. R. S. Moraes , G. N. Zeminiani , M. M. Lapola