Maximum mass of a uniformly rotating neutron star

The effect of rapid uniform rotation on the upper mass limit for neutron stars is studied under the assumption that the equation of state is subject to only a minimal set of physical constraints. For given ranges of the energy condition, microstability constraint, and causality constraint, the maximum mass of a uniformly rotating neutron star is about 24-25 percent greater than the corresponding nonrotating maximum mass. The obtained value is compared with that of the maximum mass of uniformly rotating configurations associated with the stiffest of the equations of state proposed for actual neutron-star matter. Rotation increases the upper limit on baryon mass by only about 20 percent, while the limiting moment of inertia is about twice its value for the nonrotating case. Upper limits are also found for the frequency of rotation, the frequency of frame dragging, and the maximum polar and equatorial redshifts. Discarding the causality constraint would allow the upper mass limit to increase by a given value. 16 references