PROBING THE ECLIPSE REGION OF A BINARY MILLISECOND PULSAR

We report the discovery of a new eclipsing millisecond binary pulsar s ystem, PSR J2051-0827, The pulsar has a period of 4.5 ms and is in a v ery compact circular orbit with a companion of mass similar to 0.03 M( .). Observations at low frequencies show that the eclipse duration is approximately 10% of the orbital period, However, at high radio freque ncies, pulses are often detected throughout the eclipse region, reveal ing interesting time-variable density structure in the eclipsing plasm a.