Scale: Image is 6 arcmin on a side.
| Cassiopeia A: supernova remnant, shell type (infrared view) | 19/08/1999 | ||
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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. Scale: Image is 6 arcmin on a side. |
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| Image Credit: ISO. | |||
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| 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 infrared image of Cas A shows dust grains that have been swept up and heated to several hundred degrees by the expanding hot gas. It is not known whether the dust grains were ejected by the star millions of years before it exploded or during the explosion. | |
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