Red Giant Stars Red Giants are very large, cool and luminous stars. This stage lasts about 10% of the stars life. They are old stars meaning they don't have much lifetime left. Red giant phase occurs in stars, which weigh less than 4 solar masses. The star starts to collapse towards the centre causing the star to heat up. The fusion rate increases within the outer shells; this causes the star to expand. The surface cools, making …showed first 75 words of 602 total…

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