A NEW BINARY MILLISECOND PULSAR

A 4.57 ms pulsar, PSR J1713 + 0747, in a 67.8 day binary orbit with a low-mass (>0.28 M.) companion has been detected in a systematic search of the sky at high Galactic latitudes with the Arecibo radio telescope. The new pulsar is characterized by a weak magnetic field of 1.9 x 10(8) G and a spin-down age of 8.9 +/- 1.0 Gyr, making it probably one of the oldest neutron stars currently observed. The distance to the pulsar is approximately 0.8 kpc as indicated by its dispersion measure. Small timing residuals (approximately 1 mus), a relatively large flux density at GHz frequencies (S1400 approximately 3 mJy), and a narrow, sharply peaked pulse morphology, make PSR J1713 + 0747 a new celestial clock of extraordinary precision and a rare target for VLBI frame-tie experiments.