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In the paper we discuss equilibrium states of stars, using a simplified analytic model. A star is considered as self-graviting body of gas. We use a condition for the equilibrium state of the body in the form of a differential equation,…

General Physics · Physics 2015-04-23 Andrei Smirnov , Ricardo Max Menezes Oliveira

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

We study a new class of equilibrium two-parametric distribution functions of spherical stellar systems with radially anisotropic velocity distribution of stars. The models are less singular counterparts of the so called generalized…

Astrophysics of Galaxies · Physics 2015-06-16 E. V. Polyachenko , V. L. Polyachenko , I. G. Shukhman

We perform fully relativistic calculations of binary neutron stars in corotating, circular orbit. While Newtonian gravity allows for a strict equilibrium, a relativistic binary system emits gravitational radiation, causing the system to…

General Relativity and Quantum Cosmology · Physics 2016-08-25 T. W. Baumgarte , G. B. Cook , M. A. Scheel , S. L. Shapiro , S. A. Teukolsky

Within the framework of Einstein-Gauss-Bonnet theory in five-dimensional spacetime ($5D$ EGB), we derive the hydrostatic equilibrium equations and solve them numerically to obtain neutron stars for both isotropic and anisotropic…

General Relativity and Quantum Cosmology · Physics 2024-10-15 Juan M. Z. Pretel , Ayan Banerjee , Anirudh Pradhan

Two-dimensional models of rapidly rotating stars are already unavoidable for the interpretation of interferometric or asteroseismic data of this kind of stars. When combined with time evolution, they will allow the including of a more…

Solar and Stellar Astrophysics · Physics 2015-06-17 Michel Rieutord , Francisco Espinosa Lara

We have proposed a new model of dark energy star consisting of five zones namely, solid core of constant energy density, the thin shell between core and interior, an inhomogeneous interior region with anisotropic pressures, thin shell and…

General Physics · Physics 2015-02-10 Piyali Bhar , Farook Rahaman

We prove existence of solutions for an elastic body interacting with itself through its Newtonian gravitational field. Our construction works for configurations near one given by a self-gravitating ball of perfect fluid. We use an implicit…

General Relativity and Quantum Cosmology · Physics 2015-06-18 Lars Andersson , Robert Beig , Bernd G. Schmidt

This paper investigates the existence and properties of stable, uniformly rotating star-planet systems, i.e. mass ratio is sufficiently small. It is modeled by the Euler-Poisson equations. Following the framework established by McCann for…

Analysis of PDEs · Mathematics 2026-04-22 Hangsheng Chen

A new class of solutions describing analytical solutions for compact stellar structures has been developed within the tenets of General Relativity. Considering the inherent anisotropy in compact stars, a stable and causal model for…

General Relativity and Quantum Cosmology · Physics 2021-10-14 Jay Solanki , Bhashin Thakore

A class of general relativistic solutions in isotropic spherical polar coordinates are discussed which describe compact stars in hydrostatic equilibrium. The stellar models obtained here are characterized by four parameters, namely,…

Solar and Stellar Astrophysics · Physics 2015-06-17 Rumi Deb , Bikash Chandra Paul , Ramesh Tikekar

The unknown state of matter at ultra-high density, large proton/neutron number asymmetry, and low temperature is a major long-standing problem in modern physics. Neutron stars provide the only known setting in the Universe where matter in…

Modified theories of gravity that offer viable models for dark energy often rely on mechanisms that screen their effects in high density environments. From this perspective, it would appear that, once solar system constraints are satisfied,…

General Relativity and Quantum Cosmology · Physics 2020-07-24 Bernardo F. de Aguiar , Raissa F. P. Mendes

We show that the mass-radius $(M-R)$ relation corresponding to the stiffest equation of state (EOS) does not provide the necessary and sufficient condition of dynamical stability for the equilibrium configurations, since such configurations…

Astrophysics · Physics 2009-11-13 P. S. Negi

Models of neutron and strange stars are considered in the approximation of a uniform density distribution. A universal algebraic equation, valid for any equation of state, is used to find the approximate mass of a star of a given density…

High Energy Astrophysical Phenomena · Physics 2026-01-13 G. S. Bisnovatyi-Kogan , E. A. Patraman

Depending on the density reached in the cores of neutron stars, such objects may contain stable phases of novel matter found nowhere else in the Universe. This article gives a brief overview of these phases of matter and discusses…

Astrophysics · Physics 2017-08-23 David Blaschke , Thomas Klaehn , Fridolin Weber

Modelling isolated rotating stars at any rotation rate is a challenge for the next generation of stellar models. These models will couple dynamical aspects of rotating stars, like angular momentum and chemicals transport, with classical…

Solar and Stellar Astrophysics · Physics 2015-06-11 Michel Rieutord , Francisco Espinosa Lara

We consider perfect fluid bodies ("stars") in general relativity that are axisymmetric, asymptotically flat, and that admit a maximal hypersurface. We show that configurations that extremize the total entropy at fixed ADM mass, ADM angular…

General Relativity and Quantum Cosmology · Physics 2015-09-15 Joshua S. Schiffrin

The relativistic equations of hydrostatic equilibrium for a spherically symmetric star, or the Tolman-Oppenheimer-Volkoff equations are known in higher dimensions. In this paper, these equations have been expressed in terms of parameters of…

General Relativity and Quantum Cosmology · Physics 2020-10-21 Manjari Bagchi

In the present paper, we treat the problem of the existence of quark stars (QSs) for selected homogeneous and unpaired charge-neutral $3$-flavor interacting quark matter with $\mathcal{O}(m_s^4)$ corrections equations of state (EoS). Using…

General Relativity and Quantum Cosmology · Physics 2021-06-02 Grigoris Panotopoulos , Takol Tangphati , Ayan Banerjee , M. K. Jasim