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.
A supernova of a star more than about 10 times the size of our sun may leave behind the densest objects in the universe— black holes. The Crab Nebula is the leftover, or remnant, of a massive star in our Milky Way that died 6,500 light-years away.
A supernova is what happens when a star has reached the end of its life and explodes in a brilliant burst of light.