Is something wrong with the binary pulsar

It is argued that the optical source seen at the position of the binary pulsar PSR 1913 + 16 may be the pulsar sphere, that is, a region of confined extremely relativistic plasma glowing in the near IR, and that the secondary is another neutron star. Therefore, the optical coincidence need not cause any doubt to be cast on the published general relativistic analysis of this system. The binary pulsar's likely history and the possible presence of a second binary pulsar in Cas A are considered. (UK)