The Life of a Star
2 marks · EasyExplain why a star changes colour as it evolves from a red giant into a white dwarf.
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Common mistakes: Stating colour changes without mentioning temperature
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Marking points
M1 · 1 mark · Explains the change is due to change in surface temperature.
M1 · 1 mark · Correctly describes red giant is cooler (red) and white dwarf is hotter (blue/white).
Worked solution
As the star contracts after the red giant stage, its surface temperature increases. Cooler stars emit more red light; as the star heats up, it emits blue and white light, so it appears white as a white dwarf.