Pan of Cassiopeia A

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 Webb’s Mid-InfraRed Instrument (MIRI) to reveal Cas A in a new light.

On the remnant’s exterior, particularly at the top and left, lie curtains of material appearing orange and red that are due to emission from warm dust. This marks where ejected material from the exploded star is ramming into surrounding circumstellar material. 

Interior to this outer shell lie mottled filaments of bright pink studded with clumps and knots. This represents material from the star itself, and likely shines by the light produced by a mix of heavy elements and dust emission. The stellar material can also be seen as fainter wisps near the cavity’s interior.

A loop represented in green extends across the right side of the central cavity. Its shape and complexity are unexpected and challenging for scientists to understand.