Rotating neutron star structure - Implications of the millisecond pulsar PSR 1937 + 214

Abstract

Rapidly rotating fluid objects of a given mass can remain stable only up to a critical angular speed, beyond which they may undergo instabilities leading to disruption. A semi-Newtonian condition of rotational stability applied to the recently discovered millisecond pulsar PSR 1937 + 214 implies lower bounds on the mass and moment of inertia and an upper bound on the radius of the neutron star. These upper and lower bounds are dependent on the equation of state of high-density neutron matter. Critically rotating realistic neutron star models are constructed using the prescription of Hartle and Thorne (1968), for six representative equations of state. The lower bounds on mass are found to be substantially higher than previous estimates. Results for various equations of state of neutron matter at high densities are compared with observational data for neutron star masses.