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Related papers: Compact stars in Rastall gravity: hydrostatic equi…

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We study radial perturbations of general relativistic stars with elastic matter sources. We find that these perturbations are governed by a second order differential equation which, along with the boundary conditions, defines a…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Max Karlovini , Lars Samuelsson , Moundheur Zarroug

We calculate static and spherically symmetric solutions for the Rastall modification of gravity to describe Neutron Stars (NS). The key feature of the Rastall gravity is the non-conservation of the energy-momentum tensor proportionally to…

General Relativity and Quantum Cosmology · Physics 2016-10-24 A. M. Oliveira , H. E. S. Velten , J. C. Fabris , L. Casarini

We consider the dynamics of porous icy dust aggregates in a turbulent gas disk and investigate the stability of the disk. We evaluate the random velocity of porous dust aggregates by considering their self-gravity, collisions, aerodynamic…

Earth and Planetary Astrophysics · Physics 2017-06-28 Shugo Michikoshi , Eiichiro Kokubo

Nuclear rings at centers of barred galaxies exhibit strong star formation activities. They are thought to undergo gravitational instability when sufficiently massive. We approximate them as rigidly-rotating isothermal objects and…

Astrophysics of Galaxies · Physics 2016-09-28 Woong-Tae Kim , Sanghyuk Moon

One of the stiffest equations of state for matter in a compact star is constant energy density and this generates the interior Schwarzschild radius to mass relation and the Misner maximum mass for relativistic compact stars. If dark matter…

Solar and Stellar Astrophysics · Physics 2016-03-25 José P. S. Lemos , Francisco J. Lopes , Gonçalo Quinta , Vilson T. Zanchin

This paper explores the viability and stability of compact stellar objects characterized by anisotropic matter in the framework of $f(\mathrm{Q},\mathrm{T})$ theory, where $\mathrm{Q}$ denotes non-metricity and $\mathrm{T}$ represents the…

General Relativity and Quantum Cosmology · Physics 2024-07-08 M. Zeeshan Gul , M. Sharif , Adeeba Arooj

Perturbations of rotating relativistic stars can be classified by their behavior under parity. For axial perturbations (r-modes), initial data with negative canonical energy is found with angular dependence $e^{im\phi}$ for all values of…

General Relativity and Quantum Cosmology · Physics 2009-10-30 John L. Friedman , Sharon M. Morsink

We obtain well behaved interior solutions describing hydrostatic equilibrium of anisotropic relativistic stars in scale-dependent gravity, where Newton's constant is allowed to vary with the radial coordinate throughout the star. Assuming…

General Relativity and Quantum Cosmology · Physics 2021-01-26 Grigoris Panotopoulos , Angel Rincon , Ilidio Lopes

We solve the dynamical GR equations for the spherically symmetric evolution of compact stars in the vicinity of the maximum mass, for which instability sets in according to linear perturbation theory. The calculations are done with the…

General Relativity and Quantum Cosmology · Physics 2015-08-06 Alessandro Brillante , Igor Mishustin

We present a rigorous proof establishing the mathematical equivalence between two independent criteria for the marginal stability of multi-fluid relativistic stars: the dynamical criterion based on the vanishing of the fundamental radial…

High Energy Astrophysical Phenomena · Physics 2025-12-02 Tian-Shun Chen , Xiao-Ding Zhou , Kilar Zhang

In this paper, we study the viability and stability of anisotropic compact stars in the context of $f(\mathcal{Q})$ theory, where $\mathcal{Q}$ is non-metricity scalar. We use Finch-Skea solutions to investigate the physical properties of…

General Relativity and Quantum Cosmology · Physics 2024-01-18 Muhammad Zeeshan Gul , Shamaila Rani , Muhammad Adeel , Abdul Jawad

In this work we study rapidly rotating stars by considering the Rastall theory of gravity. We obtain and solve the equations by numerical methods for two usual parametrization of polytropic stars. Then the mass-radius relations, moments of…

High Energy Astrophysical Phenomena · Physics 2022-01-05 F. M. da Silva , L. C. N. Santos , C. C. Barros

In this work, we develop a new relativistic model for a charged anisotropic compact star in the framework of modified symmetric teleparallel gravity, namely $f(Q)$-Euler-Heisenberg gravity. By employing the MIT bag model equation of state,…

General Relativity and Quantum Cosmology · Physics 2025-12-03 Allah Ditta , M. Yousaf , G. Mustafa , S. K. Maurya , Farruh Atamurotov , Orhan Donmez , Sardor Murodov

We develop a numerical algorithm for the solution of the Sturm-Liouville differential equation governing the stationary radial oscillations of nonrotating compact stars. Our method is based on the Numerov's method that turns the…

General Relativity and Quantum Cosmology · Physics 2020-05-06 Francesco Di Clemente , Massimo Mannarelli , Francesco Tonelli

We perform the general relativistic stability analysis against radial oscillations of unpaired quark stars obtained using the equation of state for cold quark matter from perturbative QCD, the only free parameter being the renormalization…

High Energy Physics - Phenomenology · Physics 2020-01-03 José C. Jiménez , Eduardo S. Fraga

In the metric approach of $f(R)$ theories of gravity, the fourth-order field equations are often recast as effective Einstein equations in the presence of standard matter and a curvature fluid (which gathers all the extra terms), always in…

General Relativity and Quantum Cosmology · Physics 2020-12-01 Juan M. Z. Pretel , Sergio E. Jorás , Ribamar R. R. Reis

In the framework of Teleparallel Gravity, we derive a charged non-vacuum solution for a physically symmetric tetrad field with two unknown functions of radial coordinate. The field equations result in a closed-form adopting particular…

General Relativity and Quantum Cosmology · Physics 2020-12-02 Gamal G. L. Nashed , Salvatore Capozziello

We present the first interior solutions representing compact stars in $\kappa(\mathcal{R},\mathcal{T})$ gravity, by solving the modified field equations in isotropic coordinates. Further, we have assumed the metric potentials in…

General Relativity and Quantum Cosmology · Physics 2022-12-02 Ginés R. Pérez Teruel , Ksh. Newton Singh , Farook Rahaman , Tanmoy Chowdhury

We consider static spherically symmetric self-gravitating configurations of the perfect fluid within the framework of the torsion-based extended theory of gravity. In particular, we use the covariant formulation of $f(T)$ gravity with $f(T)…

General Relativity and Quantum Cosmology · Physics 2018-10-03 Sasa Ilijic , Marko Sossich

This work is based on stability analysis of spherically symmetric collapsing star surrounding in locally anisotropic environment in $f(R,T)$ gravity, where $R$ is Ricci scalar and $T$ corresponds to the trace of energy momentum tensor.…

General Physics · Physics 2014-11-26 Ifra Noureen , M. Zubair