STRUCTURE OF RAPIDLY ROTATING NEUTRON-STARS

We extend the powerful numerical code for rotating general relativistic polytropes to realistic neutron stars. We compute the fully general relativistic structure of rapidly rotating neutron stars for several kinds of equations of state of neutron star matter. We solve models for two rotation laws: uniform rotation and differential rotation. For uniformly rotating models our results are in good agreement with those previously obtained when the strength of the gravity is not large. For the equation of state by Friedman & Pandharipande, however, the maximum angular velocity of our models is several per cent larger than that obtained by Friedman, Ipser & Parker. For differentially rotating neutron stars, we compute models whose angular velocities near the polar region are approximately 30 per cent larger than those near the equatorial region.