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Related papers: Collapsing spherical stars in f(R) gravity

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This paper investigates the viability and stability of anisotropic compact stars in the framework of $f(\mathcal{R},\mathrm{T}^{2})$ theory ($\mathcal{R}$ is the Ricci scalar and…

General Relativity and Quantum Cosmology · Physics 2023-05-31 M. Sharif , Sana Manzoor

This paper analyses the cosmological consequences of a modified theory of gravity whose action integral is built from a linear combination of the Ricci scalar $R$ and a quadratic term in the covariant derivative of $R$. The resulting…

General Relativity and Quantum Cosmology · Physics 2015-12-31 R. R. Cuzinatto , C. A. M. de Melo , L. G. Medeiros , P. J. Pompeia

The unknown physical nature of the Dark Energy motivates in cosmology the study of modifications of the gravity theory at large distances. One of these types of modifications is to consider gravity theories, generally termed as $f(R)$. In…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-07 Pedro Bessa , Marcela Campista , Armando Bernui

Extended gravity is widely constrained in different astrophysical and astronomical systems. Since these different systems are based on different scales it is not trivial to get a combined constraint that is based on different phenomenology.…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-02 D. Benisty , J. Mifsud , J. Levi Said , D. Staicova

We obtain a class of anisotropic spherically symmetric relativistic solutions of compact objects in hydrostatic equilibrium in the $f(R,T) =R+2\chi T$ modified gravity, where $R$ is the Ricci scalar, $T$ is the trace of the energy momentum…

General Physics · Physics 2020-09-18 S. Dey , A. Chanda , B. C. Paul

Modified gravity is one of the potential candidates to explain the accelerated expansion of the universe. Current study highlights the materialization of anisotropic compact stars in the context of $f(R,G)$ theory of gravity. In particular,…

General Physics · Physics 2017-07-07 M. Farasat Shamir , Saeeda Zia

We study the interior spacetimes of stars in the Palatini formalism of f(R) gravity and derive a generalized Tolman-Oppenheimer-Volkoff and mass equation for a static, spherically symmetric star. We show that matching the interior solution…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Kimmo Kainulainen , Vappu Reijonen , Daniel Sunhede

We investigate f(R) theories of gravity within the Palatini approach and show how one can determine the expansion history, H(a), for an arbitrary choice of f(R). As an example, we consider cosmological constraints on such theories arising…

Astrophysics · Physics 2008-11-26 M. Amarzguioui , O. Elgaroy , D. F. Mota , T. Multamaki

Several authors have argued that self-consistent $f(R)$ gravity models distinct from $\Lambda $CDM are almost ruled out. Confronting such claims, we present a particular two-parameter $f(R)$ model that: (a) is cosmologically viable and…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-18 V Miranda , Sergio E. Joras , Ioav Waga , Miguel Quartin

Spherical scalar collapse in f(R) gravity is studied numerically in double-null coordinates in the Einstein frame. Dynamics in the vicinity of the singularity of the formed black hole is examined via mesh refinement and asymptotic analysis.…

General Relativity and Quantum Cosmology · Physics 2014-07-15 Jun-Qi Guo , Daoyan Wang , Andrei V. Frolov

We apply the recent results in Loop Quantum Cosmology and in the resolution of Black Hole singularity to the gravitational collapse of a star. We study the dynamic of the space time in the interior of the Schwarzschild radius. In particular…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Leonardo Modesto

Stochastic perturbations (radial) of a spherically symmetric relativistic star, modeled by a perfect fluid in comoving coordinates for the collapse scenario are worked out using the classical Einstein- Langevin equation, which has been…

General Relativity and Quantum Cosmology · Physics 2019-04-09 Seema Satin

In this paper, we study the existence of strange star in the background of f (T) modified gravity where T is a scalar torsion. In KB metric space, we derive the equations of motion using anisotropic property within the spherically strange…

General Relativity and Quantum Cosmology · Physics 2018-10-25 Pameli Saha , Ujjal Debnath

We study both analytically and numerically the gravitational fields of stars in f(R) gravity theories. We derive the generalized Tolman-Oppenheimer-Volkov equations for these theories and show that in metric f(R) models the Parameterized…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Kimmo Kainulainen , Johanna Piilonen , Vappu Reijonen , Daniel Sunhede

We consider the effect of a logarithmic f(R) theory, motivated by the form of the one-loop effective action arising from gluons in curved spacetime, on the structure of relativistic stars. In addition to analysing the consistency…

General Relativity and Quantum Cosmology · Physics 2013-12-16 Hamzeh Alavirad , Joel M. Weller

The effects implied for the structure of compact objects by the modification of General Relativity produced by the generalization of the Lagrangian density to the form f(R)=R+\alpha R^2, where R is the Ricci curvature scalar, have been…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-24 Mariana Orellana , Federico García , Florencia Anabella Teppa Pannia , Gustavo Esteban Romero

Numerical investigation of the static spherically symmetric vacuum solution of the Logunov equations confirms the analytical results and demonstrates a strong repulsion at sub-Planckian distance from the Schwarzschild-like singularity,…

Astrophysics · Physics 2007-05-23 Vladimir L. Kalashnikov

This work aims to investigate the behaviour of compact stars in the background of $f(R, T)$ theory of gravity. For current work, we consider the Krori-Barua metric potential i.e., $\nu(r)= Br^2+C$ and $\lambda(r)= Ar^2,$ where, $A, B$ and…

General Relativity and Quantum Cosmology · Physics 2023-04-13 M. Farasat Shamir , Zoya Asghar , Adnan Malik

We develop a theoretical framework to study slowly rotating compact stars in a rather general class of alternative theories of gravity, with the ultimate goal of investigating constraints on alternative theories from electromagnetic and…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Paolo Pani , Emanuele Berti , Vitor Cardoso , Jocelyn Read

We establish an exact bidirectional map between interior Friedmann density of a collapsing star and exterior static spherically symmetric metric in generalized Oppenheimer-Snyder collapse. This reduces Einstein's differential…

General Relativity and Quantum Cosmology · Physics 2026-05-12 H. Khodabakhshi , Zhi-Chao Li , H. Lu , F. Shojai
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