Rapidly Rotating Neutron Star Models

Results are reported from a numerical investigation of the structure of rapidly rotating relativistic models based on equations of state (EOS) proposed for neutron star matter. Sequences of rotating stars with baryon mass approximately equal to 1.4 solar mass were constructed using a number of EOSs. Along each sequence the angular velocity increases from zero to the Keplerian frequency that marks the termination point. Stability limits on the star's angular velocity are estimated for the various EOSs, and models at termination are examined for five representative EOSs in order to find upper limits on mass, baryon mass, moment of inertia, and red and blueshifts for each EOS. Several sequences of models with angular velocity ranging from zero up to the angular velocity of a particle in circular orbit at the equator are described. The implications of the results for the growth times for nonaxisymmetric instability, axisymmetric instability, the fast pulsar, neutron star spin-up via accretion, and oblateness effects in pulsar spindowns are discussed.