Cassiopeia A: supernova remnant , shell type 19/08/1999
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Optical (MDM Obs) X-ray (NASA/CXC/SAO)
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Infrared (ISO) Radio (VLA)
Cas A is the remnant of a star that exploded about 300 years ago. The X-ray image shows an expanding shell of hot gas produced by the explosion. This gaseous shell is about 10 light years in diameter, and has a temperature of about 50 million degrees.
Constellation: Cassiopeia

Optical view
X-ray view
Infrared view
Radio view

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Image Credit: See individual images.  
These images show Cas A as viewed by four different types of telescopes. The X-ray image of the Cassiopeia A supernova remnant on the left is the official first light image of the Chandra X-ray Observatory. The 5,000 second image was made with the Advanced CCD Imaging Spectrometer (ACIS). 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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