What gives a star its colour?
Find out why stars come in different colours
Generally, the colour of a star is an indication of the temperature of its surface. Image credit: NASA/JPL-Caltech/2MASS
Asked by Sarah Boyle
Certain stars appear to have a tint of colour. Generally, the colour of a star is an indication of the temperature of its surface. Stars are giant nuclear reactors, producing energy that excites or gives energy to electrons. When these subatomic particles lose this energy, they emit radiation, mainly as visible and infrared (heat). The hotter the star, the greater the average energy of the radiation emitted. The possible colours of visible light are found within a spectrum, or rainbow. Blue light has a shorter wavelength and higher energy than red light, indicating that the surface temperature of a blue star is higher than that of a red star. And our own Sun? A yellow, mid-temperature star!
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