The binary pulsar: Preexplosion evolution

Data on PSR 1913+16 including the rotation of periastron, omega-dot=4degree-dot-below24 +- 0degreex04 yr-1, which is interpreted as a purely relativistic effect, are used to estimate the masses in the system at various stages in its evolution. The mass of the pulsar is found to be less than 1.82 M/sub sun/. The mass of the collapsed companion has probably changed little since it was formed, the estimate for its mass being in the range 1-2.7 M/sub sun/. The prepulsar star prior to explosion is found to have greater than the minimal Chandrasekhar mass approx.1.4 M/sub sun/. Prior to the final stage of mass transfer the system probably resembled Cen X-3 with a compact object orbiting a primary of 8-12 M/sub sun/