How do stars get their colors?

The primary reason stars exhibit different colors is their surface temperature. A star's color is a direct indicator of how hot its surface is, with hotter stars appearing blue or white and cooler stars appearing yellow, orange, or red.1

Astronomers categorize stars by their spectral class, which is based on these temperature-related color differences. The relationship between temperature and color is generally as follows:

• Blue to bluish white: These are the hottest stars, with surface temperatures exceeding 10,000 kelvins (K).1
• White: Class A stars, with temperatures ranging from 7,400 to 10,000 K.1
• Yellow-white: Class F stars, with temperatures between 6,000 and 7,400 K.1
• Yellow: Class G stars, such as the Sun, which have temperatures between 5,000 and 6,000 K.1
• Yellow to orange: Class K stars, with temperatures of approximately 3,500–5,000 K.1
• Red: Class M stars, which are cooler, at about 3,000 K.1

While temperature is the main factor, the specific appearance of a star's spectrum can also be influenced by its atmospheric density, chemical composition, and the presence of specific elements that absorb light at different wavelengths.234