Supernovae can expel several solar masses of material at speeds up to several percent of the speed of light. This drives an expanding shock wave into the surrounding interstellar medium, sweeping up an expanding shell of gas and dust observed as a supernova remnant.
supernova, any of a class of violently exploding stars whose luminosity after eruption suddenly increases many millions of times its normal level. The term supernova is derived from nova (Latin: “new”), the name for another type of exploding star.