A Supernova Cocoon Breakthrough
On November 3, 2010, a supernova was discovered in the galaxy UGC 5189A, located about 160 million light years away. Using data from the All Sky Automated Survey telescope in Hawaii taken earlier, astronomers determined this supernova exploded in early October 2010 (in Earth’s time-frame).
This composite image of UGC 5189A shows X-ray data from Chandra in purple and optical data from Hubble Space Telescope in red, green and blue. SN 2010jl is the very bright X-ray source near the top of the galaxy. A team of researchers used Chandra to observe this supernova, which was one of the most luminous that has ever been detected in X-rays.
The X-rays from the explosion’s blast wave were strongly absorbed by a cocoon of dense gas around the supernova, which was formed by gas blown away from the massive star before it exploded. Then, the blast wave from the explosion broke out of the cocoon and heated the surrounding gas to very high temperatures — greater than 100 million °K — making it glow in X-rays.
In short, the matter around the supernova has been heated and ionized (electrons stripped from atoms) by the X-rays generated when the blast wave plows through this material. This discovery therefore supports the idea that some of the unusually luminous supernovas are caused by the blast wave from their explosion ramming into the material around it.