# What happens to a star after it has become a red giant?

When our sun reaches the end of its lifetime , it will turn into a red giant. How long will it be a red giant, and what happens after a star has been a red giant? Does it turn into a planet after a long enough time spent, when it has used up all its helium?

• No, the Sun will not turn into a red dwarf. Red dwarf stars theoretically will cool down over time -- but none have yet done so because they do so over a time span longer than the current age of the Universe. – Keith Thompson Nov 5 '13 at 20:08
• You might want to update your title and question, changing "red dwarf" to "red giant". – Keith Thompson Nov 7 '13 at 2:20

It will become a planetary nebula like e.g. the Cat's Eye nebula that was formed by the death of a star with about the same mass as the Sun ~ $1\ M_\odot$: