OBSERVATIONAL CONSTRAINTS ON THE NEUTRON-STAR MASS-DISTRIBUTION

Radio observations of neutron star binary pulsar systems have constrained strongly the masses of eight neutron stars. Assuming neutron star masses are uniformly distributed between lower and upper bounds m(l) and m(u), the observations determine with 95% confidence that 1.01 < m(l)/M. < 1.34 and 1.43 < m(u)/M. < 1.64.. These limits give observational support to neutron star formation scenarios that suggest that masses should fall predominantly in the range 1.3 < m/M. < 1.6, and will also be important in the interpretation of binary inspiral observations by the Laser Interferometer Gravitational-wave Observatory.