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We use a modified Einstein-Maxwell gravity to study stability of an electrostatic spherical star. Correction terms in this model are scalers which are made from contraction of Ricci tensor and electromagnetic vector potential. Our…

General Relativity and Quantum Cosmology · Physics 2023-12-05 Hossein Ghaffarnejad , Tohid Ghorbani , Firoozeh Eidizadeh

Polytropic stars are useful tools for learning about stellar structure without the complexity of comprehensive stellar models. These models rely on a certain power-law correlation between the star's pressure and density. This paper proposes…

General Relativity and Quantum Cosmology · Physics 2024-07-19 Akashdip Karmakar , Ujjal Debnath , Pramit Rej

We study the weakly nonlinear evolution of acoustic instability of a plane- parallel polytrope with thermal dissipation in the form of Newton's law of cooling. The most unstable horizontal wavenumbers form a band around zero and this…

Astrophysics · Physics 2009-10-30 O. M. Umurhan , L. Tao , E. A. Spiegel

A model approach to the description of static stars filled with a charged Pascal perfect fluid within the framework of general relativity is investigated. The metric is written in Bondi's radiation coordinates. The gravitational equations…

General Relativity and Quantum Cosmology · Physics 2012-01-24 A. M. Baranov

In the de Sitter gauge theory (DGT), the fundamental variables are the de Sitter (dS) connection and the gravitational Higgs/Goldstone field $\xi^A$. Previously, a model for DGT was analyzed, which generalizes the MacDowell--Mansouri…

General Relativity and Quantum Cosmology · Physics 2021-06-15 Jia-An Lu

In this manuscript, we study the behavior of charged isotropic compact stellar objects within the framework of the modified Gauss-Bonnety theory of gravity by considering the Tolman Kuchowicz spacetime. We use some matching conditions of…

General Relativity and Quantum Cosmology · Physics 2024-06-25 Adnan Malik

The inner structure of a star or a primordial interstellar cloud is a major topic in classical and relativistic physics. The impact that General Relativistic principles have on this structure has been the subject of many research papers. In…

General Relativity and Quantum Cosmology · Physics 2019-08-14 Mayer Humi , John Roumas

A new class of relativistic stellar structure equations which include the effects of an energy-dependent Newton coupling is presented. Significant modifications in the mass-radius relation for neutron stars are possible only if the running…

General Relativity and Quantum Cosmology · Physics 2020-01-16 Alfio Bonanno , Roberto Casadio , Alessia Platania

The modified Lane-Emden equation for stellar hydrostatic equilibrium in f(R)-gravity is numerically solved by using an iterative procedure. Such an integro-differential equation can be obtained in the weak field limit approximation of…

Solar and Stellar Astrophysics · Physics 2015-06-17 R. Farinelli , M. De Laurentis , S. Capozziello , S. D. Odintsov

In this paper Einstein's field equations, for static spherically symmetric perfect fluid models with a linear barotropic equation of state, are recast into a 3-dimensional regular system of ordinary differential equations on a compact state…

General Relativity and Quantum Cosmology · Physics 2009-10-31 U. S. Nilsson , C. Uggla

It is proposed that the Higgs vacuum possesses a small-scale structure that can explain the large discrepancy between the predicted electroweak vacuum energy density and the observed cosmological constant. An effective Lagrangian…

High Energy Physics - Phenomenology · Physics 2008-08-04 Paolo Amore , Alfredo Aranda , J. Lorenzo Diaz-Cruz

A general formalism to find the density profile of a slowly rotating stellar object in modified gravity is presented. We derive a generic Lane-Emden equation and its analytical solution for a wide class of modified theories of gravity.

General Relativity and Quantum Cosmology · Physics 2022-12-23 Shaswata Chowdhury , Pritam Banerjee , Aneta Wojnar

The structure of a star composed of locally non-electroneutral incompressible three-component matter is considered within the framework of general relativity. For thermodynamic quantities like the pressure, the solution can be represented…

High Energy Astrophysical Phenomena · Physics 2021-12-22 N. I. Kramarev , A. V. Yudin

This work is devoted to investigate some of the interior configuration of static anisotropic spherical stellar charged structures in the regime of $f(\mathcal{G})$ gravity, where $\mathcal{G}$ is the Gauss Bonnet invariant. The structure of…

General Physics · Physics 2018-09-24 Muhammad Ilyas

The Lagrangian theory of structure formation in cosmological fluids, restricted to the matter model ``dust'', provides successful models of large-scale structure in the Universe in the laminar regime, i.e., where the fluid flow is…

Astrophysics · Physics 2011-05-23 Susanne Adler , Thomas Buchert

In unimodular-like theories, the constants of nature are demoted from pre-given parameters to phase space variables. Their canonical duals provide physical time variables. We investigate how this interacts with an alternative approach to…

High Energy Physics - Theory · Physics 2023-12-12 Paolo M Bassani , Joao Magueijo

Topological structure has been extensively studied and confirmed in highly correlated condensed matter physics. We explore the gravitational waves emitted from binary neutron star mergers using the pseudoconformal model for dense nuclear…

Nuclear Theory · Physics 2021-07-07 Wen-Cong Yang , Yong-Liang Ma , Yue-Liang Wu

This paper is devoted to study the stability/instability of the expansionfree self gravitating source in the framework of Einstein Gauss-Bonnet gravity. The source has been taken as Tolman-Bondi model which is homogenous in nature. The…

General Relativity and Quantum Cosmology · Physics 2015-04-22 G. Abbas , S. Sarwar

We present a new formulation for numerically obtaining axisymmetric equilibrium structures of rotating stars in two spatial dimensions. With a view to apply it to the secular evolution of rotating stars, we base it on the Lagrangian…

Solar and Stellar Astrophysics · Physics 2023-03-15 Misa Ogata , Hirotada Okawa , Kotaro Fujisawa , Nobutoshi Yasutake , Yu Yamamoto , Shoichi Yamada

We explore static spherically symmetric stars in the Gauss-Bonnet gravity without cosmological constant, and present an exact internal solution which attaches to the exterior vacuum solution outside stars. It turns out that the presence of…

General Relativity and Quantum Cosmology · Physics 2015-05-28 Kang Zhou , Zhan-Ying Yang , De-Cheng Zou , Rui-Hong Yue