OBSERVATIONAL CONSTRAINTS ON THE MAXIMUM NEUTRON-STAR MASS

We review estimates of the mass of the compact core in SN 1987A and co nclude that the most accurate determination can be obtained from the k nown value of similar to 0.075 M(.) of Ni production in the explosion With binding energy correction, this gives an upper limit of gravitati onal mass of similar to 1.56 M(.), slightly larger than Brown & Bethe' s previous estimate of similar to 1.5 M(.). Observation by OSSE of the ratio of gamma-rays from Co-57 and Co-56 indicates that neutron-rich material from the inner regions does not reach the mass cut by convect ion or Rayleigh-Taylor instability. Arguments that the core of SN 1987 A went into a black hole are reviewed. If one accepts this to be true, then the maximum compact core mass gives an upper limit on neutron st ar masses of (M(NS))(max) congruent to 1/56 M(.) (gravitational), in r ough agreement with the previous result of Brown & Bethe.