Calculations of mass and moment of inertia for neutron stars

Abstract

Masses and moments of inertia for slowly-rotating neutron stars are calculated from the Tolman-Oppenheimer-Volkoff equations and various equations of state for neutron-star matter. We have also obtained pressure and density as a function of the distance from the centre of the star. Generally, two different equations of state are applied for particle densities n > 0.47 fm −3 and n < 0.47 fm −3. The maximum mass is, in our calculations for all equations of state except for the unrealistic non-relativistic ideal Fermi gas, given by 1.50 M ⊙ < M < 1.82 M ⊙, which agrees very well with “experimental results”. Corresponding results for the maximum moment of inertia are 9.5 × 10 44 g · cm 2 < I < 1.58 × 10 45 g · cm 2, which also seem to agree very well with “experimental results”. The radius of the star corresponding to maximum mass and maximum moment of inertia is given by 8.2 km < R < 10.0 km, but a smaller central density ρ c will give a larger radius.