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Related papers: Approximate Spacetime for Neutron Stars

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We present new sequences of general relativistic, quasiequilibrium black hole-neutron star binaries. We solve for the gravitational field in the conformal thin-sandwich decomposition of Einstein's field equations, coupled to the equations…

Astrophysics · Physics 2009-11-11 Keisuke Taniguchi , Thomas W. Baumgarte , Joshua A. Faber , Stuart L. Shapiro

Models of neutron stars are considered in the case of a uniform density distribution. An algebraic equation, valid for any equation of state, is obtained. This equation allows one to find the approximate mass of a star of a given density…

High Energy Astrophysical Phenomena · Physics 2023-11-14 G. S. Bisnovatyi-Kogan , E. A. Patraman

For a variety of fully relativistic polytropic neutron star models we calculate the star's tidal Love number k2. Most realistic equations of state for neutron stars can be approximated as a polytrope with an effective index n~0.5-1.0. The…

Astrophysics · Physics 2009-03-20 Tanja Hinderer

Set of neutron star observational results is used to test some selected equations of state of dense nuclear matter. The first observational result comes from the mass--baryon number relation for pulsar B of the double pulsar system J…

Solar and Stellar Astrophysics · Physics 2010-07-21 Martin Urbanec , Emil Betak , Zdenek Stuchlik

The universal relations in neutron stars form an essential entity to understand their properties. The moment of inertia, dimensionless tidal deformability, mass quadrupole moment, and oscillation modes are some of the properties that have…

High Energy Astrophysical Phenomena · Physics 2025-08-13 Sagnik Chatterjee , Kamal Krishna Nath

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

Numerical models of rotating neutron stars are constructed for four equations of state using the computer code RNS written by Stergioulas. For five selected values of the star's gravitational mass (in the interval between 1.0 and 1.8 solar…

General Relativity and Quantum Cosmology · Physics 2015-06-25 William G. Laarakkers , Eric Poisson

We consider the circular motion of test particles in the gravitational field of a rotating deformed object described by the Hartle-Thorne metric. This metric represents an approximate solution to the vacuum Einstein field equations,…

General Relativity and Quantum Cosmology · Physics 2023-06-28 Yergali Kurmanov , Marco Muccino , Kuantay Boshkayev , Talgar Konysbayev , Orlando Luongo , Hernando Quevedo , Ainur Urazalina

We present a brief review of general results about non-rotating neutron stars in simple R-square gravity and its extension with a scalar axion field. Modified Einstein equations are presented for metrics in isotropical coordinates. The…

General Relativity and Quantum Cosmology · Physics 2020-07-08 Artyom V. Astashenok , Sergei D. Odintsov

An approximate solution to Einstein's equations representing two widely-separated non-rotating black holes in a circular orbit is constructed by matching a post-Newtonian metric to two perturbed Schwarzschild metrics. The spacetime metric…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Kashif Alvi

I review attempts made to determine the properties of neutron stars. The focus is on the maximum mass that a neutron star can have, or, conversely, the minimum mass required for the formation of a black hole. There appears to be only one…

Astrophysics · Physics 2009-10-31 M. H. van Kerkwijk

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…

We construct parameter sets of the relativistic mean-field model fitted to the recent constraints on the asymmetry energy $J$ and the slope parameter $L$ for pure neutron matter. We find cases of unphysical behaviour, i.e.\ the appearance…

High Energy Astrophysical Phenomena · Physics 2018-12-19 Nadine Hornick , Laura Tolos , Andreas Zacchi , Jan-Erik Christian , Jürgen Schaffner-Bielich

Neutrino asymmetry in general relativistic radiative spacetime exterior to spinning stars is investigating by making use of Newmann-Penrose (NP) spin coefficient formalism. It is shown that neutrino current depends on the direction of…

General Relativity and Quantum Cosmology · Physics 2010-11-19 L. C. Garcia de Andrade

Equilibria of binary neutron stars in close circular orbits are computed numerically in a waveless formulation: The full Einstein-relativistic-Euler system is solved on an initial hypersurface to obtain an asymptotically flat form of the…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Koji Uryu , Francois Limousin , John L. Friedman , Eric Gourgoulhon , Masaru Shibata

We compute the axial quasi-normal modes of static neutron stars in scalar tensor theory. In particular, we employ various realistic equations of state including nuclear, hyperonic and hybrid matter. We investigate the fundamental curvature…

General Relativity and Quantum Cosmology · Physics 2018-08-29 Zahra Altaha Motahar , Jose Luis Blázquez-Salcedo , Burkhard Kleihaus , Jutta Kunz

Neutron stars are the densest objects known in the Universe. Being the final product of stellar evolution, their internal composition and structure is rather poorly constrained by measurements. It is the purpose of this paper to put some…

High Energy Astrophysical Phenomena · Physics 2015-05-19 J. Petri

The long-standing controversy about the isospin dependence of the effective Dirac mass in ab initio calculations of asymmetric nuclear matter is clarified by solving the relativistic Brueckner-Hartree-Fock equations in the full Dirac space.…

Nuclear Theory · Physics 2022-08-30 Sibo Wang , Hui Tong , Qiang Zhao , Chencan Wang , Peter Ring , Jie Meng

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

The equation of state of matter at supranuclear densities governs the astrophysical observables of neutron stars. A realistic, though complex, description is provided by the Chiral-Mean-Field model, which depends on many microscopic…

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