Introduction
In the night sky, stars display a range of colors from blue to red. These differences are not random but reflect underlying physical properties of the stars.
Temperature and Color Temperature
The surface temperature of a star determines its emitted color. Hot stars (above 10,000 K) emit predominantly blue light, while cooler stars (below 3,000 K) appear mainly red. Color temperature, measured in Kelvin, describes the hue of an ideal black‑body with the same brightness.
Spectral Classes and Chemical Composition
Spectral classes—O through M—categorize stars by temperature and chemical makeup. Blue and white stars belong to the O and B classes, orange and red stars to the K and M classes. Spectral lines reveal elements such as hydrogen, helium, and metals.
Distance and Interstellar Dust Effects
Stellar colors can be altered by interaction with interstellar dust. Redder light is scattered more strongly, so stars viewed across large distances often appear redder—a phenomenon known as reddening or redshift.
Conclusion
The visible colors of stars are a direct result of their temperature, composition, and the distance their light travels. By studying these colors, astronomers gain critical insights into stellar physics and evolution.