planetary-nebulae

Most of the carbon in your body was not made in a supernova. It was made in the bloated outer layers of a dying star on the asymptotic giant branch — a phase of stellar evolution so chemically productive that a single AGB star can enrich the surrounding interstellar medium with more carbon than a thousand supernovae. These stars pulse, dredge up nuclear-processed material from their interiors, and blow it into space in slow, dense winds that eventually become planetary nebulae.

Nebulae are vast clouds of gas and dust between stars. Some are stellar nurseries where new stars form, some are shells shed by dying stars, and some are the debris of supernova explosions. The Orion Nebula is a nursery visible to the naked eye; the Crab Nebula is the expanding wreckage of a star that exploded in 1054.