The color of a star is primarily determined by its composition size apparent brightness age surface temperature

The correct

The color of a star is primarily determined by its Surface temperature.

The explanation:

-Stars emit colors of many different wavelengths, but the wavelength of light where a star's emission is concentrated is related to the star's temperature - the hotter the star, the bluer it is; the cooler the star, the redder it is.

The surface temperature is used to estimate the wavelength that radiated within. the star with lower wavelength tends to have purple-ish color, while the one with higher wavelength tends to have orange-ish color.

For example, the really hot stars, called White Dwarf stars, have a white surface temperature, while a cooler star would have a more red color.

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