Death of a Sun-like Star


[Note: This page is the second part of the story of the death of the Sun.
You may want to have a look at the first part]


2nd RG phase Just like in the first Red Giant phase, the outside of the star will grow until it takes up a large part of the entire Solar System, and the centre will shrink and heat up again.

White Dwarf However, it will never get hot enough to start making energy with any other nuclear fuel, and so the outer parts of the star will grow and cool and eventually fade away leaving just the hot, small core.

White Dwarf This core is now very strange indeed. It has shrunk so much that it is only about the same size as the Earth, but has almost all of the mass of the Sun in it! It is producing no more new energy, but it is very hot (100,000 °C or more). It will now just sit there and very slowly cool down. This strange dead star is called a White Dwarf.

PN If we now move very far away from the White Dwarf we can see what has happened to the bits of the star that were blown off during the Red Giant phases. This forms a big shell of glowing gas around the White Dwarf called a Planetary Nebula (They are called this because early astronomers thought that they looked a bit like planets. They are not planets of course!)

If you want, you can see an animation of the death of the Sun.
[Warning: Large file (280 Kbyte). You may need special software to see the animation]

You can also see what happens to much larger stars when they die


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