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Using time evolutions of the relevant linearised equations we study non-axisymmetric oscillations of rapidly rotating and superfluid neutron stars. We consider perturbations of Newtonian axisymmetric background configurations and account…

Astrophysics · Physics 2009-11-13 Andrea Passamonti , Brynmor Haskell , Nils Andersson

In this paper we classify the free boundary associated to equilibrium configurations of compressible, self-gravitating fluid masses, rotating with constant angular velocity. The equilibrium configurations are all critical points of an…

Analysis of PDEs · Mathematics 2012-10-16 Sagun Chanillo , Georg S. Weiss

Stationary and axisymmetric solutions of relativistic rotating stars with strong mixed poloidal and toroidal magnetic fields are obtained numerically. Because of the mixed components of the magnetic field, the underlying stationary and…

High Energy Astrophysical Phenomena · Physics 2014-11-13 Koji Uryu , Eric Gourgoulhon , Charalampos Markakis , Kotaro Fujisawa , Antonios Tsokaros , Yoshiharu Eriguchi

In recent works we have constructed axisymmetric solutions to the Euler-Poisson equations which give mathematical models of slowly uniformly rotating gaseous stars. We try to extend this result to the study of solutions of the…

Analysis of PDEs · Mathematics 2018-09-26 Tetu Makino

The hydrodynamic evolution of self-gravitating gaseous stars is governed by the Euler-Poisson equations. We study the structure of the linear approximation of barotropic perturbations around spherically symmetric equilibria based on…

Analysis of PDEs · Mathematics 2020-05-15 Juhi Jang , Tetu Makino

We construct steady states of the Euler-Poisson system with a barotropic equation of state as minimizers of a suitably defined energy functional. Their minimizing property implies the non-linear stability of such states against general,…

Mathematical Physics · Physics 2009-11-07 Gerhard Rein

Rotating relativistic stars are receiving significant attention in recent years, because of the information they can yield about the equation of state of matter at extremely high densities and because they are one of the more possible…

General Relativity and Quantum Cosmology · Physics 2016-10-19 Nikolaos Stergioulas

We use time-evolutions of the linear perturbation equations to study the oscillations of rapidly rotating neutrons stars. Our models account for the buoyancy due to composition gradients and we study, for the first time, the nature of the…

Astrophysics · Physics 2009-11-13 A. Passamonti , B. Haskell , N. Andersson , D. I. Jones , I. Hawke

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

We study nonaxisymmetric perturbations of rotating relativistic stars. modeled as perfect-fluid equilibria. Instability to a mode with angular dependence $\exp(im\phi)$ sets in when the frequency of the mode vanishes. The locations of these…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Nikolaos Stergioulas , John L. Friedman

A typical galaxy consists of a huge number of stars attracted to each other by gravity. For instance, the Milky Way has about $10^{11}$ stars. Thus it is typically modeled by the Vlasov-Poisson system. We prove an existence theorem for…

Analysis of PDEs · Mathematics 2022-03-04 Walter A. Strauss , Yilun Wu

Stellar pulsations in rotating relativistic stars are reviewed. Slow rotation approximation is applied to solving the Einstein equations. The rotational effects on the non-axisymmetric oscillations are explicitly shown in the polar and…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Yasufumi Kojima

The dynamics of gaseous stars can be described by the Euler-Poisson system. Inspired by Rein's stability result for $\gamma>{4/3}$, we prove the nonlinear instability of steady states for the adiabatic exponent $\gamma={6/5}$ in spherically…

Analysis of PDEs · Mathematics 2007-05-23 Juhi Jang

This article reports results from numerical simulations of the gravitational radiation emitted from nonrotating relativistic stars as a result of the axisymmetric accretion of layers of perfect fluid matter, shaped in the form of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Alessandro Nagar , Guillermo Diaz

Non-axisymmetric oscillations of differentially rotating stars are studied using both slow rotation and Cowling approximation. The equilibrium stellar models are relativistic polytropes where differential rotation is described by the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Andrea Passamonti , Adamantios Stavridis , Kostas Kokkotas

This paper presents a systematic study of the properties of non-rotating stellar models governed by the Euler-Poisson system under general equations of state, including the case of polytropic gaseous stars. We revisit and extend existence…

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

We consider a two-dimensional, incompressible fluid body, together with self-induced interactions. The body is perturbed by an external particle with small mass. The whole configuration rotates uniformly around the common center of mass. We…

Analysis of PDEs · Mathematics 2026-02-25 Diego Alonso-Orán , Bernhard Kepka , Juan J. L. Velázquez

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

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

We study spherically symmetric motions of a gaseous star governed by the Euler-Poisson equations. Equilibria are given as solutions of the Lane-Emden equations, and the linearized equation around one of these equilibria admits time-periodic…

Analysis of PDEs · Mathematics 2015-08-21 Tetu Makino