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A simple classification is given of the anisotropic relativistic star models, resembling the one of charged isotropic solutions. On the ground of this database, and taking into account the conditions for physically realistic star models, a…

General Relativity and Quantum Cosmology · Physics 2018-01-24 B. V. Ivanov

It is shown that for realistic anisotropic star models the surface redshift can not exceed the values 3.842 or 5.211 when the tangential pressure satisfies the strong or the dominant energy condition respectively. Both values are higher…

General Relativity and Quantum Cosmology · Physics 2009-11-07 B. V. Ivanov

A class of solutions of Einstein field equations satisfying Karmarkar embedding condition is presented which could describe static, spherical fluid configurations, and could serve as models for compact stars. The fluid under consideration…

General Relativity and Quantum Cosmology · Physics 2021-03-24 Lipi Baskey , Shyam Das , Farook Rahaman

Neutron stars may exhibit pressure anisotropy arising from various physical mechanisms, such as elasticity, magnetic fields, viscosity, and superfluidity. We compute the tidal deformability and the $f$-mode oscillation frequency of…

High Energy Astrophysical Phenomena · Physics 2026-02-17 Victor Guedes , Siddarth Ajith , Shu Yan Lau , Kent Yagi

In this article we obtain a new anisotropic solution for Einstein's field equation of embedding class one metric. The solution is representing the realistic objects such as $Her~X-1$ and $RXJ~1856-37$. We perform detailed investigation of…

General Physics · Physics 2016-04-27 S. K. Maurya , Y. K. Gupta , Baiju Dayanandan , Saibal Ray

In this paper, we develop a new class of models for a compact star with anisotropic stresses inside the matter distribution. By assuming a linear equation of state for the anisotropic matter composition of the star we solve the Einstein…

General Relativity and Quantum Cosmology · Physics 2021-11-16 Shyam Das , Saibal Ray , Maxim Khlopov , K. K. Nandi , Bikram Keshari Parida

Simple generic extensions of isotropic Durgapal--Fuloria stars to the anisotropic domain are presented. These anisotropic solutions are obtained by guided minimal deformations over a self gravitating isotropic system. When the isotropic and…

General Relativity and Quantum Cosmology · Physics 2018-07-04 Luciano Gabbanelli , Ángel Rincón , Carlos Rubio

We studied a new class of interior solutions that are singular-free and useful for describing anisotropic compact star objects with spherically symmetric matter distribution. We have considered metric potential selecting B_0^2…

General Relativity and Quantum Cosmology · Physics 2023-10-19 B. S. Ratanpal , Rinkal Patel

We find new exact solutions to the Einstein-Maxwell field equations which are relevant in the description of highly compact stellar objects. The relativistic star is charged and anisotropic with a quark equation of state. Exact solutions of…

General Relativity and Quantum Cosmology · Physics 2017-01-04 D. Kileba Matondo , S. D. Maharaj

We model a compact radiant star that undergoes gravitational collapse from a certain initial static configuration until it becomes a black hole. The star consists of a fluid with anisotropy in pressures, bulk viscosity, in addition to the…

General Relativity and Quantum Cosmology · Physics 2023-04-26 A. C. Mesquita , M. F. A. da Silva

Motivated by the recent suggestions that very massive pulsar (PSR J0952-0607) and very light compact object (HESS J1731-347) exist, in this article, we revisit the possibility of such objects being strange stars instead of the standard…

High Energy Astrophysical Phenomena · Physics 2023-09-06 H. C. Das , Luiz L. Lopes

Anisotropic stresses are ubiquitous in nature, but their modeling in General Relativity is poorly understood and frame dependent. We introduce the first study on the dynamical properties of anisotropic self-gravitating fluids in a covariant…

General Relativity and Quantum Cosmology · Physics 2019-06-05 Guilherme Raposo , Paolo Pani , Miguel Bezares , Carlos Palenzuela , Vitor Cardoso

The cosmological principle is fundamental to the standard cosmological model. It assumes that the Universe is homogeneous and isotropic on very large scales. As the basic assumption, it must stand the test of various observations. In this…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-13 J. P. Hu , Y. Y. Wang , J. Hu , F. Y. Wang

We investigate anisotropic compact stars in the non-minimal $Y(R)F^2$ model of gravity which couples an arbitrary function of curvature scalar $Y(R)$ to the electromagnetic field invariant $F^2$. After we obtain exact anisotropic solutions…

General Relativity and Quantum Cosmology · Physics 2018-10-17 Özcan Sert , Fatma Çeliktaş , Muzaffer Adak

It is well known that a spherically symmetric compact star whose energy density decreases monotonically possesses an upper bound on its mass-to-radius ratio, $2M/R\leq 8/9$. However, field configurations typically will not be compact. Here…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Shahar Hod

Pressure isotropy, i.e., equality between radial and tangential pressure, is often assumed when studying neutron stars. However, mechanisms such as pion/kaon condensation, magnetic fields, and dark matter clustering can lead to pressure…

High Energy Astrophysical Phenomena · Physics 2026-03-16 Peter T. H. Pang , Stephanie M. Brown , Thibeau Wouters , Chris Van Den Broeck

We investigated Rastall gravity, for an anisotropic star with a static spherical symmetry, whereas the matter-geometry coupling as assumed in Rastall Theory (RT) is expected to play a crucial role in differentiating RT from General…

General Relativity and Quantum Cosmology · Physics 2022-09-07 G. G. L. Nashed , W. El Hanafy

Certain physical quantities that characterize neutron stars and quark stars (e.g. their mass, spin angular momentum and quadrupole moment) are interrelated in a way that is approximately insensitive to their internal structure. Such…

General Relativity and Quantum Cosmology · Physics 2024-07-23 Kent Yagi , Nicolas Yunes

The main aim of this study is to examine the behaviour of physical parameters of an anisotropic compact star model demonstrating spherical symmetry in F(Q) modified gravity. To evaluate the behaviour and the stability of an anisotropic…

General Relativity and Quantum Cosmology · Physics 2025-05-26 Sat Paul , Jitendra Kumar , S. K. Maurya

We lay down the foundations of particle dynamics in mechanical theories that satisfy the relativity principle and whose kinematics can be formulated employing reference frames of the type usually adopted in special relativity. Such…

General Relativity and Quantum Cosmology · Physics 2009-06-30 Sebastiano Sonego , Massimo Pin