H0850-42

K. S. Wood and J. P. Norris, Naval Research Laboratory, Washington, write: "During a systematic search of HEAO A-1 point maneuver data we have found a new x-ray pulsar. It has been detected at least ten separate times. The period has a mean value of 1.779 s and ranges from 1.7787 to 1.7794 s, indicating that the source is in a binary system. The position is restricted to a region with corners at R.A. = 8h30m, Decl. = -46.5; R.A. = 8h38m, Decl. = -47.5; R.A. = 8h54m, Decl. = -38.0; R.A. = 9h04m, Decl. = -39.5. The center of this region is the most likely position, and we therefore designate the source as H0850-42. The mean measured x-ray pulsed flux is roughly 0.05 Uhuru flux units. The true flux, corrected for responses, should be 3 to 10 times higher than this, depending on the precise position. Further x-ray observations are needed to refine the position and determine the orbit parameters."