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Related papers: Polytropic stars in Palatini gravity

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Two exact solutions for $n=0$ and $n=1$ of the Palatini-modified Lane-Emden equation are found. We have employed these solutions to describe a Palatini-Newtonian neutron star and compared the result with the pure Newtonian counterpart. It…

General Relativity and Quantum Cosmology · Physics 2020-04-22 A. Sergyeyev , A. Wojnar

We will briefly discuss the necessary conditions for stability of polytropies in $f(\hat R)$ Palatini gravity and the differences with the General Relativity ones.

General Relativity and Quantum Cosmology · Physics 2020-01-03 Aneta Wojnar

We examine static spherically symmetric polytropic spheres in Palatini f(R) gravity and show that no regular solutions to the field equations exist for physically relevant cases such as a monatomic isentropic gas or a degenerate electron…

General Relativity and Quantum Cosmology · Physics 2011-08-31 Enrico Barausse , Thomas P. Sotiriou , John C. Miller

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

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

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

Spherically symmetric relativistic stars with the polytropic equation of state, which possess the local pressure anisotropy, are considered in the context of general relativity. The modified Lane-Emden equations are derived for the special…

General Relativity and Quantum Cosmology · Physics 2018-01-25 A. A. Isayev

Non-vacuum static spherically-symmetric solutions in Palatini f(R) gravity are examined. It is shown that for generic choices of f(R), there are commonly-used equations of state for which no satisfactory physical solution of the field…

General Relativity and Quantum Cosmology · Physics 2008-09-29 Enrico Barausse , Thomas P. Sotiriou , John C. Miller

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

We analyse configurations of compact stars in the so-called R-squared gravity in the Palatini formalism. Using a realistic equation of state we show that the mass-radius configurations are lighter than their counterparts in General…

General Relativity and Quantum Cosmology · Physics 2016-12-28 F. A. Teppa Pannia , F. García , S. E. Perez Bergliaffa , M. Orellana , G. E. Romero

The main subjects of the PhD dissertation concern cosmological models considered in Palatini f(R) gravity and scalar-tensor theories. We introduce a simple generalization of the LCDM model based on Palatini modified gravity with quadratic…

General Relativity and Quantum Cosmology · Physics 2016-11-01 Aneta Wojnar

Using a perturbative approach we solve stellar structure equations for low-density (solar-type) stars whose interior is described with a polytropic equation of state in scenarios involving a subset of modified gravity theories. Rather than…

Solar and Stellar Astrophysics · Physics 2019-02-27 M. Cermeño , J. Carro , A. L. Maroto , M. Ángeles Pérez-García

We consider static spherically symmetric stellar configurations in Palatini theories of gravity in which the Lagrangian is an unspecified function of the form $f(R,R_{\mu\nu}R^{\mu\nu})$. We obtain the Tolman-Oppenheimer-Volkov equations…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Gonzalo J. Olmo , Helios Sanchis-Alepuz , Swapnil Tripathi

In the present work we study strange stars in $f(R)$ theories of gravity in the Palatini formalism. We consider two concrete well-known cases, namely the $R+R^2/(6 M^2)$ model as well as the $R-\mu^4/R$ model for two different values of the…

General Relativity and Quantum Cosmology · Physics 2017-05-03 Grigoris Panotopoulos

Polytropic models play a very important role in galactic dynamics and in the theory of stellar structure and evolution. However, in general, the solution of the Lane-Emden equation can not be given analytically but only numerically. In the…

Astrophysics · Physics 2015-06-24 F. K. Liu

We investigate how the cosmological Equation of State can be used for scrutinizing extended theories of gravity, in particular, the Palatini $f(R)$ gravity. Specifically, the approach consists, at first, in investigating the effective…

General Relativity and Quantum Cosmology · Physics 2024-02-27 S. Camera , S. Capozziello , L. Fatibene , A. Orizzonte

We discuss the standard Lane-Emden formalism as well as the one related to the slowly rotating objects. It is preceded by a brief introduction of different forms of the polytropic equation of state. This allows to study a wide class of…

General Relativity and Quantum Cosmology · Physics 2024-02-12 Aneta Wojnar

We review the Palatini formulation of the higher-derivative gravity of the $L(R)$ form and its applications in cosmology.

Astrophysics · Physics 2007-05-23 Peng Wang , Xin-He Meng

We review the recent literature on modified theories of gravity in the Palatini approach. After discussing the motivations that lead to consider alternatives to Einstein's theory and to treat the metric and the connection as independent…

General Relativity and Quantum Cosmology · Physics 2011-05-09 Gonzalo J. Olmo

We consider static spherically symmetric stellar configurations in Palatini theories of gravity in which the Lagrangian is an unspecified function of the form f(R,R_{\mu\nu}R^{\mu\nu}). We obtain the Tolman-Oppenheimer-Volkov equations…

General Relativity and Quantum Cosmology · Physics 2012-11-06 Gonzalo J. Olmo , Helios Sanchis-Alepuz , Swapnil Tripathi
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