POSSIBLE OPTICAL OBSERVATION OF THE COMPANION STAR TO THE BINARY PULSAR PSR1913+16

Deep R band CCD photographs of the region surrounding the binary pulsar PSR1913 + 16 have been obtained with the 4-m telescope of the Kitt Peak National Observatory. Using an accurate astrometric solution, we find a star with M R = 20.9 at the precise coordinates of the pulsar. Possible interpretations of this result, including the unlikely (<3%) possibility that it is an accidental superposition of a field star, are discussed. If this object is the physical companion to the pulsar, it is probably a helium star. © 1979 Nature Publishing Group.