These data were retrieved from the EXOSAT satellite through their Medium
Energy experiment. The students will determine the pulsar rotation period
here, which is 4.8 seconds. This is a system where a pulsar is in orbit around
a 17 solar mass (17 x the mass of the Sun) O star (very large blue star).
This is a peculiar source where long term variations are seen in both the
pulsar period and the orbital period. It has been hypothesized that this is
due to a third "body" that may exist within this system.