| Two
shock waves are visible: a fast outer shock and a slower inner shock. The
inner shock wave is believed to be due to the collision of the ejecta from
the supernova explosion with a circumstellar shell of material, heating
it to a temperature of ten million degrees. The outer shock wave is analogous
to an awesome sonic boom resulting from this collision. The bright object
near the center may be the long sought neutron star or black hole that remained
after the explosion that produced Cas A. |
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Cas
A gets its name from radio astronomers, who rediscovered' it in 1948 as
the strongest radio source in the constellation of Cassiopeia. About 5 years
later optical astronomers found the faint wisps, and it was determined that
Cas A is the remnant of an explosion that occurred about 300 years ago.
The radio emission comes from high energy electrons moving in large spirals
around magnetic field lines of force. |
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