2008/12/31 by Andrea Passamonti, B. Haskell, Brynmor Haskell +1
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics #Classical mechanics #Geophysics and Gravity Measurements #Mechanics #Neutron star #Physics #Polytrope #Polytropic process #Pulsars and Gravitational Waves Research #Quantum mechanics #Rotation (mathematics) #Rotational symmetry #Stars #Stellar, planetary, and galactic studies #Superfluidity #Symmetry (geometry) #astro-ph #gr-qc
paper · pdf · doi:10.1111/j.1365-2966.2009.14751.x
18 pages, 7 figures, 5 tables, accepted for publication in MNRAS
arxiv created 2009/03/26 · openalex publication_date 2009/04/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Using time evolutions of the relevant linearized equations, we study non-axisymmetric oscillations of rapidly rotating and superfluid neutron stars. We consider perturbations of Newtonian axisymmetric background configurations and account for the presence of superfluid components via the standard two-fluid model. Within the Cowling approximation, we are able to carry out evolutions for uniformly rotating stars up to the mass-shedding limit. This leads to the first detailed analysis of superfluid neutron star oscillations in the fast rotation regime, where the star is significantly deformed by the centrifugal force. For simplicity, we focus on background models where the two fluids (superfluid neutrons and protons) corotate, are in β-equilibrium and co-exist throughout the volume of the star. We construct sequences of rotating stars for two analytical model equations of state. These models represent relatively simple generalizations of single fluid, polytropic stars. We study the effects of entrainment, rotation and symmetry energy on non-radial oscillations of these models. Our results show that entrainment and symmetry energy can have a significant effect on the rotational splitting of non-axisymmetric modes. In particular, the symmetry energy modifies the inertial mode frequencies considerably in the regime of fast rotation.