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A class of solutions describing the interior of a static spherically symmetric compact anisotropic star is reported. The analytic solution has been obtained by utilizing the Finch and Skea ({\it Class. Quant. Grav.} {\bf 6} (1989) 467)…

General Relativity and Quantum Cosmology · Physics 2015-06-16 Ranjan Sharma , B. S. Ratanpal

In this article, we assume that a cold charged perfect fluid is constructing a spherical relativistic star. Our purpose is the investigation of the dynamical properties of its exterior geometry, through simulating the geodesic motion of a…

General Relativity and Quantum Cosmology · Physics 2015-03-19 Mohsen Fathi

The equation of state of dense matter determines the structure of neutron stars, their typical radii, and maximum masses. Recent improvements in theoretical modeling of nuclear forces from the low-energy effective field theory of QCD has…

Nuclear Theory · Physics 2019-09-04 Jeremy W. Holt , Yeunhwan Lim

Neutron stars are the densest, directly observable stellar objects in the universe and serve as unique astrophysical laboratories to study the behavior of matter under extreme physical conditions. This book chapter is devoted to describing…

High Energy Astrophysical Phenomena · Physics 2018-06-11 N. Degenaar , V. F. Suleimanov

We develop a new method to measure neutron star parameters and derive constraints on the equation of state of dense matter by fitting the frequencies of simultaneous Quasi Periodic Oscillation modes observed in the X-ray flux of accreting…

High Energy Astrophysical Phenomena · Physics 2020-09-02 Andrea Maselli , George Pappas , Paolo Pani , Leonardo Gualtieri , Sara Motta , Valeria Ferrari , Luigi Stella

We express the Einstein-Vlasov system in spherical symmetry in terms of a dimensionless momentum variable $z$ (radial over angular momentum). This regularises the limit of massless particles, and in that limit allows us to obtain a reduced…

General Relativity and Quantum Cosmology · Physics 2017-01-04 Carsten Gundlach

We reexamine the equation of state for the nucleonic and hyperonic inner core of neutron stars that satisfies the 2$M_{\odot}$ observations as well as the recent determinations of stellar radii below 13 km, while fulfilling the saturation…

High Energy Astrophysical Phenomena · Physics 2017-12-08 Laura Tolos , Mario Centelles , Angels Ramos

Models of relativistic rotating neutron star composed of hyperon rich matter is constructed in the framework of an effective field theory in the mean-field approach. The gross properties of compact star is calculated at both static and the…

Nuclear Theory · Physics 2009-05-12 B. K. Sharma , T. K. Jha

This paper discusses a generalized model for compact stars, assumed to be anisotropic in nature due to the spherical symmetry and high density. After embedding the four-dimensional spacetime in a five-dimensional flat spacetime, which may…

General Physics · Physics 2018-03-09 S. K. Maurya , Debabrata Deb , Saibal Ray , P. K. F. Kuhfittig

The recent measurement of a $1.97\pm 0.04$ solar-mass pulsar places a stringent lower bound on the maximum mass of compact stars and therefore challenges the existence of any agents that soften the equation of state of ultra-dense matter.…

Solar and Stellar Astrophysics · Physics 2012-02-21 Luca Bonanno , Armen Sedrakian

We provide new exact solutions to the Einstein-Maxwell system of equations for matter configurations with anisotropy and charge. The spacetime is static and spherically symmetric. A quadratic equation of state is utilised for the matter…

General Relativity and Quantum Cosmology · Physics 2016-01-06 Sifiso A. Ngubelanga , Sunil D. Maharaj , Subharthi Ray

We construct models of triaxial galactic nuclei containing central black holes using the method of orbital superposition, then verify their stability by advancing N-body realizations of the models forward in time. We assume a power-law form…

Astrophysics · Physics 2009-11-07 M. Y. Poon , D. Merritt

In this review we discuss self-consistent methods to calculate the global structure of strongly magnetised neutron stars within the general-relativistic framework. We outline why solutions in spherical symmetry cannot be applied to strongly…

Nuclear Theory · Physics 2021-09-01 Debarati Chatterjee , Jerome Novak , Micaela Oertel

In this paper we investigate gravitationally bound, spherically symmetric equilibrium configurations consisting of ordinary (polytropic) matter nonminimally coupled to an external chameleon scalar field. We show that this system has static,…

Solar and Stellar Astrophysics · Physics 2012-04-03 Vladimir Folomeev , Douglas Singleton

In this work we study the structure of neutron stars under the effect of a poloidal magnetic field and determine the limiting highest magnetic field intensity which still allows a satisfactory description of magnetic neutron stars in the…

Nuclear Theory · Physics 2019-07-09 R. O. Gomes , Helena Pais , V. Dexheimer , Constança Providência , S. Schramm

Present paper deals with the composition and modelling of compact dense astrophysical bodies under the framework of $f(R)$ gravity. The model is employed on various observed strange stars viz., SMC X-1, SAX J1808.4-3658, Swift J1818.0-1607,…

General Relativity and Quantum Cosmology · Physics 2020-08-12 B. Thakore , R. Goti , S. Shah , H. Pandya , D. M. Pandya

In this article, we present a class of relativistic solutions describing spherically symmetric and static anisotropic stars in hydrostatic equilibrium. For this purpose, we consider a particularized matric potential, namely, Buchdahl ansatz…

General Relativity and Quantum Cosmology · Physics 2021-08-03 S. K. Maurya , Ayan Banerjee , M. K. Jasim , J. Kumar , A. K. Prasad , Anirudh Pradhan

We investigate the stellar structure of neutron stars in the framework of Starobinsky gravity, characterized by a quadratic correction to the Einstein-Hilbert action, $f(R) = R + \alpha R^2$. In order to {\em preserve causality…

High Energy Astrophysical Phenomena · Physics 2025-08-14 Muhammed Shafeeque , Arun Mathew , Malay K. Nandy

It is well known that a spherically symmetric constant density static star, modeled as a perfect fluid, possesses a bound on its mass m by its radial size R given by 2m/R \le 8/9 and that this bound continues to hold when the energy density…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Jemal Guven , Niall O' Murchadha

Exact models of uniformly rotating strange stars, built of self bound quark matter, are calculated within the framework of general relativity. This is made possible thanks to a new numerical technique capable to handle the strong density…

Astrophysics · Physics 2010-11-19 E. Gourgoulhon , P. Haensel , R. Livine , E. Paluch , S. Bonazzola , J. A. Marck