Crab Pulsar

The Crab pulsar is a neutron star, i.e., a stellar object composed almost entirely of neutrons.  The inset is a highly magnified box view of the central part of the entire image.  The pulsar is located at the center of both views.  It is about 10 miles in diameter and contains several solar masses.  It spins at 1818 RPM and has an exceptionally strong magnetic field, the axis of which is not coincident with the rotational axis.  Particles and radiation are "beamed" out along the magnetic field axes creating a "lighthouse" effect.  Notice the "jet" protruding right and down on the inset image.  It is caused by beamed particles colliding with material ejected by the supernova blast.  The earth is periodically illuminated by the beam and we observe regular pulses from the object; hence the term pulsar.

It has been noted by Dr. Michael Shull, University of Colorado, and others that the Crab pulsar is not located at the apparent center of the debris cloud.  Close examination places it left and below the apparent center.  It shows proper motion in that direction.  This would indicate that the supernova explosion was not symetric around the collapsed core of the progenitor star.  Asymmetry has been detected in a number of other supernova remnants.