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Spherical models of collisionless but quasi-relaxed stellar systems have long been studied as a natural framework for the description of globular clusters. Here we consider the construction of self-consistent models under the same physical…

Astrophysics · Physics 2009-11-13 G. Bertin , A. L. Varri

Context. Stars experience rapid contraction or expansion at different phases of their evolution. Modelling the angular momentum and chemical elements transport occurring during these phases remains an unsolved problem. Aims. We study a…

Solar and Stellar Astrophysics · Physics 2021-05-05 B. Gouhier , F. Lignières , L. Jouve

Since the external regions of the envelopes of rapidly rotating early-type stars are unstable to convection, a coupling may exist between the convection and the internal rotation. We explore what can be learned from spectroscopic and…

Solar and Stellar Astrophysics · Physics 2015-05-20 J. Zorec , Y. Fremat , A. Domiciano de Souza , O. Delaa , P. Stee , D. Mourard , L. Cidale , C. Martayan , C. Georgy , S. Ekstrom

We revisit the problem of inertial r-modes in stratified stars, drawing on a more precise description of the composition stratification in a mature neutron star. The results highlight issues with the traditional approach to the problem,…

General Relativity and Quantum Cosmology · Physics 2023-05-23 Nils Andersson , Fabian Gittins

Stars may be understood as self-gravitating masses of a compressible fluid whose radiative cooling is compensated by nuclear reactions or gravitational contraction. The understanding of their time evolution requires the use of detailed…

Solar and Stellar Astrophysics · Physics 2016-06-22 M. Rieutord , F. Espinosa Lara , B. Putigny

We present a novel numerical solver for the systems of coupled non-linear elliptical differential equations. The solver partitions the computational domain into a set of rectangular pseudo-spectral collocation subdomains and is especially…

General Relativity and Quantum Cosmology · Physics 2024-04-08 Nikolay Sukhov

Context: Recent calculations of pulsation modes in rapidly rotating polytropic models and models based on the Self-Consistent Field method (MacGregor et al. 2007) have shown that the frequency spectrum of low degree pulsation modes can be…

Solar and Stellar Astrophysics · Physics 2015-05-13 D. R. Reese , M. J. Thompson , K. B. MacGregor , S. Jackson , A. Skumanich , T. S. Metcalfe

Context: Rapid rotation modifies the structure of the frequency spectrum of pulsating stars, thus making mode identification difficult. Aims: We look for new forms of organisation for the frequency spectrum that can provide a basis for mode…

Astrophysics · Physics 2009-11-13 D. Reese , F. Lignières , M. Rieutord

We give a detailed description of the recently developed multi-domain spectral method for constructing highly accurate general-relativistic models of rapidly rotating stars. For both "ordinary" and "critical" configurations, it is exhibited…

Astrophysics · Physics 2010-12-23 M. Ansorg , A. Kleinwächter , R. Meinel

We present a self-consistent, relativistic model of rapidly rotating neutron stars describing their exterior gravitational field. This is achieved by matching the new solution of Einstein's field equations found by Manko et al. (2000) and…

Astrophysics · Physics 2009-11-07 Matthias Stute , Max Camenzind

We present a new formulation to construct numerically equilibrium configurations of rotating stars in general relativity. Having in mind the application to their quasi static evolutions, we adopt a Lagrangian formulation of our own…

General Relativity and Quantum Cosmology · Physics 2022-04-22 Hirotada Okawa , Kotaro Fujisawa , Nobutoshi Yasutake , Misa Ogata , Yu Yamamoto , Shoichi Yamada

Approximate analytical formula for density distribution in differentially rotating stars is derived. Any barotropic EOS and conservative rotation law can be handled with use of this method for wide range of differential rotation strength.…

Astrophysics · Physics 2007-05-23 Andrzej Odrzywolek

Although barotropic matter does not constitute a realistic model for magnetic stars, it would be interesting to confirm a recent conjecture that states that magnetized stars with a barotropic equation of state would be dynamically unstable…

Solar and Stellar Astrophysics · Physics 2015-06-15 Cristobal Armaza , Andreas Reisenegger , Juan Alejandro Valdivia , Pablo Marchant

We develop a numerical scheme for obtaining the $r$-mode oscillations of rapidly rotating relativistic stars. In the present scheme, we neglect all metric perturbations and only take account of the dynamics of the fluid in the background…

Astrophysics · Physics 2009-11-10 Shijun Yoshida , Shin'ichirou Yoshida , Yoshiharu Eriguchi

The present paper is devoted to a study of the equilibrium configurations of slowly rotating anisotropic stars in the framework of general relativity. For that purpose, we provide the equations of structure where the rotation is treated to…

General Relativity and Quantum Cosmology · Physics 2024-07-23 Philip Beltracchi , Camilo Posada

We use perturbation theory and the relativistic Cowling approximation to numerically compute characteristic oscillation modes of rapidly rotating relativistic stars which consist of a perfect fluid obeying a polytropic equation of state. We…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Stratos Boutloukos , Hans-Peter Nollert

We consider stationary axisymmetric solutions of the Euler-Poisson equations, which govern the internal structure of barotropic gaseous stars. We take the general form of the equation of states which cover polytropic gaseous stars indexed…

Analysis of PDEs · Mathematics 2019-01-25 Juhi Jang , Tetu Makino

Properties, structure, and thermal evolution of neutron stars are determined by the equation of state of stellar matter. Recent data on isospin-diffusion and isoscaling in heavy-ion collisions at intermediate energies as well as the size of…

Astrophysics · Physics 2009-11-13 Plamen G. Krastev , Bao-An Li , Aaron Worley

Outcomes of numerical relativity simulations of massive core collapses or binary neutron star mergers with moderate masses suggest formations of rapidly and differentially rotating neutron stars. Subsequent fall back accretion may also…

High Energy Astrophysical Phenomena · Physics 2017-11-29 Koji Uryu , Antonios Tsokaros , Luca Baiotti , Filippo Galeazzi , Keisuke Taniguchi , Shin'ichirou Yoshida

We consider hot accretion onto a rapidly spinning neutron star (or any other compact object with a surface). A radiative hot settling flow has been discovered at low accretion rates in the early work by Medvedev & Narayan (2001) and…

Astrophysics · Physics 2009-11-10 Mikhail V. Medvedev