Thermal conductivity of neutrons in neutron star cores

The diffusive thermal conductivity of neutrons in dense matter [rho similar to (1 - 8) x 10(14) g cm(-3)] of neutron star cores is calculated. The con tribution from neutron-neutron and neutron-proton collisions is taken into account. We use the transition probabilities calculated for symmetric dense nucleon matter on the basis of the Dirac-Brueckner approach to the in-medi um effects and the Bonn model of bare nucleon-nucleon interaction. The diff usive thermal conductivity of neutrons in the presence of neutron and proto n superfluidities is analyzed in a microscopic manner; the effects of super fluidity are shown to be significant. The low temperature behavior of the t hermal conductivity appears to be extremely sensitive to the relation betwe en critical temperatures of neutrons and protons. The results are fitted by simple analytic expressions. In combination with the formulae for the elec tron and muon thermal conductivities, obtained earlier, the present express ions provide a realistic description of the full diffusive thermal conducti vity in the neutron star cores for normal and various superfluid phases.