What is the name given to the expanding shells of ejected stellar material following a supernova?

Answer

A supernova remnant (SNR)

The immense outer layers of the star that are blasted outward form the supernova remnant, an expanding cloud of gas that glows due to shock wave heating.

What is the name given to the expanding shells of ejected stellar material following a supernova?
Materialstarsupernovaremnantejecta