X-Ray Binaries

Abstract

The end of life remains to be outlined for those objects which are too massive, concentrate much matter in the center, and lose too little to escape a supernova event. The prominent clues lie in the X-ray domain, inaccessible only a few years back. Comparatively little impact on double-star studies comes from the exploration of radio pulsars as bona-fide neutron stars and supernova remnants. One radio pulsar (PSR 1913 + 16; Hulse and Taylor, 1975) has been reported to show pulse shifts of possibly orbital origin; the large eccentricity e = 0.6 renders the case suspicious. If binary, a large apsidal motion is expected which should help in determining a pulsar mass.