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Physically based changes to general relativity (GR) often predict significant differences in how spacetime behaves near massive neutron stars. One of these modifications is represented by $f(\mathcal{Q}, { \mathcal{T}})$, with $\mathcal{Q}$…

General Relativity and Quantum Cosmology · Physics 2024-10-21 G. G. L. Nashed , Tiberiu Harko

We investigate some exact static cylindrically symmetric solutions for a perfect fluid in the metric $f(R)$ theory of gravity. For this purpose, three different families of solutions are explored. We evaluate energy density, pressure, Ricci…

General Relativity and Quantum Cosmology · Physics 2015-06-12 M. Sharif , Sadia Arif

In this paper, we have constructed a model for well behaved isotropic compact star in the presence of charged perfect fluid, by considering a static and spherically symmetric metric in Schwarzschild's canonical coordinate system. To put the…

General Relativity and Quantum Cosmology · Physics 2022-09-07 Jitendra Kumar , Puja Bharti

We introduce a rigorous and general framework to study systematically self-gravitating elastic materials within general relativity, and apply it to investigate the existence and viability, including radial stability, of spherically…

General Relativity and Quantum Cosmology · Physics 2022-06-07 Artur Alho , José Natário , Paolo Pani , Guilherme Raposo

The detection of an unexpected $\sim 2.5 M_{\odot}$ component in the gravitational wave event GW190814 has puzzled the community of High-Energy astrophysicists, since in the absence of further information it is not clear whether this is the…

High Energy Astrophysical Phenomena · Physics 2021-03-31 J. E. Horvath , P. H. R. S. Moraes

This paper investigates a spherically symmetric compact relativistic body with isotropic pressure profiles within the framework of general relativity. In order to solve the Einstein's field equations, we have considered the Vaidya-Tikekar…

Astrophysics of Galaxies · Physics 2021-11-29 Jitendra Kumar , Puja Bharti

We obtain the Buchdahl compactness limit for a pure Lovelock static fluid star and verify that the limit following from the uniform density Schwarzschild's interior solution, which is universal irrespective of the gravitational theory…

General Relativity and Quantum Cosmology · Physics 2017-06-06 Naresh Dadhich , Sumanta Chakraborty

This study presents a static, spherically symmetric configuration in which the interior geometry of a relativistic superdense star is modeled as a three-spheroid with constant $t_1$. The model is constructed using an analytical closed-form…

General Relativity and Quantum Cosmology · Physics 2026-01-07 Hemalatha R , Naren Babu O. , Narayanankutty Karuppath , Sabu M. C

General properties of neutron stars are briefly reviewed with an emphasis on the indispensability of general relativity in our understanding of these fascinating objects. In Newtonian gravity the pressure within a star merely plays the role…

High Energy Astrophysical Phenomena · Physics 2017-03-02 K. Yavuz Ekşi

We study spherically symmetric solutions to the Einstein-Euler equations which model an idealized relativistic neutron star surrounded by vacuum. These are barotropic fluids with a free boundary, governed by an equation of state which sets…

Analysis of PDEs · Mathematics 2021-08-16 Grigorios Fournodavlos , Volker Schlue

Pulse profile modeling of X-ray data from NICER is now enabling precision inference of neutron star mass and radius. Combined with nuclear physics constraints from chiral effective field theory ($\chi$EFT), and masses and tidal…

In this study we obtain interior solutions and investigate structural properties of isotropic compact stars in the framework of four-dimensional regularized Einstein-Gauss-Bonnet (4DEGB) gravity. For stellar matter content, we adopt a…

General Relativity and Quantum Cosmology · Physics 2026-01-21 G. Panotopoulos , Á. Rincón , I. Lopes

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 present the interior solutions of distributions of magnetised fluid inside a sphere in $f(R,T)$ gravity. The magnetised sphere is embedded in an exterior Reissner-Nordstr\"{o}m metric. We assume that all physical quantities are in static…

General Physics · Physics 2018-12-07 Safiqul Islam , Shantanu Basu

The study of neutron stars, or more general compact stars, is a topic of central interest in nuclear astrophysics. Furthermore, neutron stars serve as the only physical systems whose properties can be used to infer information on cold and…

Solar and Stellar Astrophysics · Physics 2013-07-19 S. Schramm , V. Dexheimer , R. Negreiros , T. Schürhoff , J. Steinheimer

We study a model of the neutron star in $\kappa$-deformed space-time in the presence of the cosmological constant ($\Lambda$). The Einstein tensor and the energy-momentum tensor are generalized to $\kappa$-deformed space-time and we…

General Relativity and Quantum Cosmology · Physics 2025-02-25 Bhagya. R , Diganta Parai , Harsha Sreekumar , Suman Kumar Panja

Apparent (radiation) radius of neutron star,R_\infty, depends on the star gravitational mass in quite a different way than the standard coordinate radius in the Schwarzschild metric, R. We show that, for a broad set of equations of state of…

Astrophysics · Physics 2009-11-06 P. Haensel

As per general relativity (GR), there cannot be any superluminal propagation of energy. And thus, the sound speed in a continuous medium, $c_s=\sqrt{dp/d\rho}$, must be subluminal. However, if one would conceive of a {\em homogeneous}…

General Physics · Physics 2011-05-02 Abhas Mitra

An anisotropic fluid with variable energy density and negative pressure is proposed, both outside and inside stars. The gravitational field is constant everywhere in free space (if we neglect the local contributions) and its value is of the…

General Relativity and Quantum Cosmology · Physics 2015-05-27 Hristu Culetu

Very recently the NICER collaboration has published the first-ever accurate measurement of mass and radius together for PSR J0030+0451, a nearby isolated quickly-rotating neutron star (NS). In this work we set the joint constraints on the…

High Energy Astrophysical Phenomena · Physics 2020-04-29 Jin-Liang Jiang , Shao-Peng Tang , Yuan-Zhu Wang , Yi-Zhong Fan , Da-Ming Wei