PSR 51012+5307 - A 5.26-MS PULSAR IN A 14.5-H BINARY-SYSTEM

We report the discovery of PSR J1012 + 5307, a 5.26-ms pulsar found during the course of a survey for short-period pulsars with the 76-m Lovell radio telescope at Jodrell Bank. The pulsar is in a 14.5-h circular orbit with a companion star of mass greater than or similar to 0.11 M(circle dot) , typical of a low-mass white dwarf. The dispersion measure of 9.0 cm(-3) pc suggests a distance of similar to 520 pc. This relatively small distance, together with a galactic latitude of 51 degrees, makes the binary system an excellent candidate for optical studies. Indeed, from an inspection of the Palomar sky survey plate, we have identified a 19th-magnitude star that lies well within the positional error box obtained from pulse arrival time measurements. If the star were the companion star to J1012 + 5307, then the age of the system would be much smaller than the characteristic age of the pulsar would suggest. Further optical observations of this system are required to confirm this possibility.