Electron-muon heat conduction in neutron star cores via the exchange of transverse plasmons

Abstract

We calculate the thermal conductivity of electrons and muons κeµ produced owing to electromagnetic interactions of charged particles in neutron star cores and show that these interactions are dominated by the exchange of transverse plasmons (via the Landau damping of these plasmons in nonsuperconducting matter and via a specific plasma screening in the presence of proton superconductivity). For normal protons, the Landau damping strongly reduces κeµ and makes it temperature independent. Proton superconductivity suppresses the reduction and restores the Fermi-liquid behavior κeµ ∝ T −1 . Comparing with the thermal conductivity of neutrons κn, we obtain κeµ κn for T 2 × 10 9 K in normal matter and for any T in superconducting matter with proton critical temperatures Tcp 3 × 10 9 K. The results are described by simple analytic formulae. PACS numbers: 52.25.Fi, 95.30.Tg, 97.20.Rp, 97.60.Jd II. ELECTRON-MUON THERMAL CONDUCTIVITY IN NORMAL MATTERThe electrons and muons in a neutron star core constitute strongly degenerate almost ideal Fermi gases [1]. The electrons are ultrarelativistic. The muons can be

Theory of cooling neutron stars versus observations

“…Superfluidity affects also neutron star heat capacity [19] and thermal conductivity [30,31] but these effects are less strong.…”

A young cooling neutron star in the remnant of Supernova 1987A

“…The solid and dashed lines indicate the thermal conductivity in a nonsuperfluid core and in the presence of proton superfluidity, respectively. Superfluidity increases the thermal conductivity, because it suppresses the scattering of electrons, muons, and neutrons by protons and changes the plasma screening via charged particle scattering (Shternin and Yakovlev 2007). Curves l indicate the thermal conductivity without including the Landau damping.…”

“…However, as was shown by Heiselberg and Pethick (1993) (for a plasma of relativistic quarks), including the Landau damping can reduce appreciably the thermal conductivity. Shternin and Yakovlev (2007) reconsidered κ eµ by taking into account the Landau damping and showed that (in the absence of superfluidity) the Landau damping reduces κ eµ below κ n , so that κ ≈ κ n .…”

Transport coefficients in superfluid neutron stars

“…In Ref. [29] the calculations of the electron-muon contribution to the thermal conductivity have been revised. We find that thermal conductivity in the neutron star core is dominated by phononphonon collisions when phonons are in a hydrodynamical regime [9].…”