Previous Year Question

The colour of a star primarily depends on its surface temperature. Stars appear in different colours because they have different temperatures. According to NASA, hotter stars generally appear blue or blue-white, whereas cooler stars appear orange or red.

This is because the distribution of radiation emitted by a star changes with its temperature. At higher temperatures, more energy is emitted toward shorter wavelengths, making hotter stars appear bluer.

Therefore, among the given options, a star's colour primarily depends on its surface temperature, not on its distance from Earth, air pollution or pressure.