Stellar Death

Not even a star can live forever. It eventually uses up the fuel that sustains its nuclear reactor, so it stops producing energy. But the form of that death can be both dramatic and beautiful. And it can help give birth to new stars — a circle of life that plays out throughout the cosmos.
A star shines by “fusing” together lightweight elements in its core to make heavier ones. For most of its long lifetime, that process is powered by hydrogen, the lightest element of all.
And for the least-massive stars, that may be all there is. Hundreds of billions of years of hydrogen fusion may create a hot, dense lump of ash that spends more billions of years simply cooling and fading from sight.
For the most-massive stars, though, the story is much different. These stars consume their hydrogen in a hurry. Their cores then shrink and get hotter, allowing them to burn heavier and heavier elements.
Eventually, though, such a star can no longer produce energy in its core. The core collapses to form a