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arXiv · 1705.06027

Temperature-dependent r-modes in superfluid neutron stars stratified by muons

Elena M. Kantor·Mikhail E. Gusakov
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Abstract

We calculate the finite-temperature r-mode spectrum of a slowly rotating superfluid Newtonian neutron star neglecting the entrainment between neutron and proton liquid components (i.e., neglecting the off-diagonal element of the entrainment matrix). We show that for `minimal' NS core composition (neutrons, protons, and electrons) only two $m=2$ r-modes exist --- normal mode, which is similar to ordinary r-mode in a nonsuperfluid star, and a superfluid temperature-dependent mode. Accounting for muons in the core dramatically modifies the oscillation spectrum, resulting in an infinite set of superfluid r-modes, whose frequencies vary with temperature. We demonstrate that the normal r-mode can exhibit avoided crossings with superfluid modes at certain `resonance' temperatures, where it dissipates strongly, which leads to substantial suppression of the r-mode instability near these temperatures. The corresponding instability windows are calculated and discussed.

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Elena M. Kantor, Mikhail E. Gusakov. 2017-05-17. Temperature-dependent r-modes in superfluid neutron stars stratified by muons. https://doi.org/10.1093/mnras%2Fstx1075

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