StarChild Question of the Month for January 2002

Question:

Do stars last forever?

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Answer:

No. Stars are born, live, and die. This process is called the "life cycle of a star". Most of the time a star shines, it is in a stage of its life cycle called the main sequence. How long it stays in the main sequence phase depends on how much mass the star has. Very big stars have a lot of mass to use as nuclear fuel to make it glow. However, they use that fuel at a very big rate. So, even though they are big, they live the shortest lives. You can see the typical main sequence lifetimes of stars of various masses in the table below.

Mass of the Star Compared to our Sun

Typical Lifetime in Years

15

500,000

3

400,000,000

1

10,000,000,000

0.4

200,000,000,000

What happens to a star when it runs out of nuclear fuel also depends on how much mass it started out with. You can read more about this in the StarChild section on Stars.

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