How Does A Star Die?

Most stars die very slowly. It takes them several million years to die. When a star like the sun has burned up all its hydrogen supply, it expands and becomes a red giant.

It can then reach a size of several million kilometres in diameter, large enough to swallow the planets, Mercury and Venus.

After its outer layers have flaked off, the star collapses and becomes an extremely dense white dwarf.

One teaspoon of the material that makes up a white dwarf would weigh up to 100 tons.

In the course of many billions of years, the white dwarf cools down and finally becomes invisible.

The life of stars, however, which weigh more than eight times the mass of the sun, ends very suddenly.

When they have used up their fuel, they swell to become red supergiants.

By resorting to other fuel, they try to prolong their life. But this works ‘only’ a few million years.

Finally, a huge explosion, a so-called supernova, occurs and they burst.

For more or less a week, the supernova shines brighter than all the other stars in its galaxy.

Then it extinguishes in a short time, leaving nothing but a tiny, dense structure called a neutron star or black hole surrounded by an expanding, red-hot cloud of gas.

The elements formed inside the supergiant (for example oxygen, carbon and iron) spread out into space.

From this stardust, new stars and planets may one day rise again.

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