1994A&A...291..155S

A new and precise numerical code for computing equilibrium configurations of relativistic rotating bodies has been used to construct "realistic" rotating neutron star models. Fourteen equations of state including recent dense matter models have been employed. Detailed comparisons of our results with previous studies have been performed. Maximum mass and maximum angular velocity models are presented and confronted with the constraints imposed by observed pulsars. A special emphasis is put on the construction of rotating configurations along sequences of constant baryon number, which may represent evolutionary sequences of rotating neutron stars. Two kinds of such sequences have been identified: the normal sequences which connect to the non-rotating limit and whose stars have a baryon number lower than the maximum one supported by static configurations and the supramassive sequences which do not connect to the non-rotating limit, its stars having a baryon number above the maximum one supported by static configurations. A remarkable feature of supramassive stars is the phenomenon of spin-up by loss of angular momentum which takes place just before the star enters the regime of instability with respect to axisymmetric perturbations. In contrast, such a behavior has not been observed for normal stars.