Supernova Remnant
Muora Supernova Remnant Remnant
Image from Steve Bowers
The Muora Supernova Remnant, formed from the explosion of a Wolf-Rayet star in 8684 AT
The expanding and cooling shell of gas and dust that is visible for thousands of years after a supernova. After a few tens of thousands of years supernova remnants mix with the interstellar medium and dissipate, or collapse into a star-forming cloud.

Where several supernovae occur in the same cluster, shockwaves and light pressure can cause nearby supernova remnant clouds to compress and collapse under their own gravity, causing new stars and planets to be formed from the debris. As the galaxy gets older, the metallicity of these star-forming clouds gradually increase, and so newly formed stars in the present era are more metal-rich than older stars that were formed in the galaxy's youth.

vela snr
Image from Steve Bowers
The Vela Supernova Remnant, an older remnant cloud which formed about 10,000 years BT.

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Development Notes
Text by M. Alan Kazlev
Initially published on 31 December 2001.