Cassiopeia A (Cas A) is a supernova remnant located about 11,000 light-years from Earth in the constellation Cassiopeia. It spans approximately 10 light-years. This new image uses data from the James Webb Space Telescope’s Mid-Infrared Instrument (MIRI) to reveal Cas A in a new light. “Cas A represents our best opportunity to look at the debris field of an exploded star and run a kind of stellar autopsy to understand what type of star was there beforehand and how that star exploded,” Danny Milisavljevic of Purdue University in Indiana, principal investigator of the Webb program that captured the new observations, said in a NASA statement on Friday (April 7 2023).