2003/02/28 by Shijun Yoshida, Umin Lee · 1 citation
Earth and Planetary Sciences · Engineering · Physics and Astronomy · #Astrophysics #Classical mechanics #Entrainment (biomusicology) #Geophysics and Gravity Measurements #Geophysics and Sensor Technology #Gravitational wave #Inertial frame of reference #Inertial wave #Instability #Mechanics #Neutron star #Physics #Pulsars and Gravitational Waves Research #Quantum mechanics #Superfluidity #Wave propagation #astro-ph #gr-qc
paper · pdf · doi:10.1046/j.1365-8711.2003.06816.x
published as Mon.Not.Roy.Astron.Soc. 344 (2003) 207 · 19 pages, 20 figures. To appear in MNRAS
arxiv created 2003/05/16 · openalex publication_date 2003/09/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We investigate the modal properties of inertial modes of rotating neutron stars with a core filled with neutron and proton superfluids, taking account of entrainment effects between the superfluids. In this paper, the entrainment effects are modelled by introducing a parameter η so that there is no entrainment state at η= 0. We find that inertial modes of rotating neutron stars with a superfluid core are split into two families, which we call ordinary fluid inertial modes (io-modes) and superfluid inertial modes (is-modes). The two superfluids in the core counter-move for the is-modes. For the io-modes, κ0= limΩ→ 0ω/Ω is only weakly dependent on the entrainment parameter η, where Ω and ω are the angular frequency of rotation and the oscillation frequency observed in the corotating frame of the star, respectively. For the is-modes, on the other hand, ∼κ0∼ increases almost linearly as η increases. Avoided crossings as functions of η are therefore quite common between io- and is-modes. We find that some of the is-modes that are unstable against the gravitational radiation reaction at η= 0 become stable when η is larger than ηcrit, the value of which depends on the mode. Since the radiation-driven instability associated with the current multipole radiation is quite weak for the inertial modes and the mutual friction damping in the superfluid core is strong, the instability caused by the inertial modes will be easily suppressed unless the entrainment parameter η is extremely small and the mutual friction damping is sufficiently weak.