Structure of rapidly rotating axisymmetric stars. I - A numerical method for stellar structure and meridional circulation

A numerical method is presented for calculating the mechanical and thermal structure of stationary axisymmetric inviscid rotating stars in which the velocity of the meridional flow is very slow. The structure of the rotating configuration is computed and the flow pattern for the given configuration is calculated. Several sequences of stationary configurations for three different rotation laws are computed. For the energy generation, the point source model is assumed and two kinds of opacities (electron scattering opacity and Kramers opacity) are examined. A two-zone flow pattern is found in the uniformly rotating models. Models with two kinds of differential rotation laws are investigated. The flow patterns in these differentially rotating models are found to be quite different from those of the uniformly rotating models. Specifically, near the rotation axis, the flow rising from the convective core directly reaches the surface of the star.