Calculation of the transport coefficients in neutron star

Abstract

In this work, we have calculated the transport coefficients: shear viscosity and thermal conductivity inside the neutron star core. Our calculation is based on the relativistic kinetic theory approach using a modified BUU equation for quasi-particles whose mass and the chemical-potential and thus in turn the Fermi surface varies with the baryonic density $ρ_{B}$ and the temperature of the medium, and we have used the relaxation time approximation. For the description of the hadronic matter inside the neutron star, we consider the relativistic mean field model with three different kinds of parameterizations. We have found that the shear viscosity is predominantly influenced by neutrons, while thermal conductivity is primarily dominated by electrons.

Figures (5)

• Figure 1: Vartion of the effective mass and chemical potential of the nucleon and lepton with density for different hadronic models
• Figure 2: Total relaxation time for nucleon (a) and lepton (b) with density.
• Figure 3: Variation of shear-viscosity (a) and thermal conductivity (b) with density for different hadronic models.
• Figure 4: Comparison of the transport coefficients obtained in the present work with calculations based on established transport formalisms: (a) shear viscosity evaluated using the SH formalism Shternin:2008es, and (b) thermal conductivity evaluated within the BHY formalism Baiko:2001cj. Both sets of calculations are performed using the IUFSU equation of state.
• Figure 5: Variation of shear-viscosity (a) and thermal conductivity (b) with density for the different temperatures for IUFSU hadronic EOS. (temperature in the figure are in MeV unit)