* Color and Temperature: The color of a star is directly related to its surface temperature. Blue stars are the hottest, followed by white, yellow, orange, and red stars, which are the coolest.

* Energy Output: Hotter stars emit more energy, and that energy peaks at shorter wavelengths (think of a hot stove glowing red, then orange, then white as it gets even hotter). Blue light has a shorter wavelength than red light.

In short: Blue stars are hotter and emit more energy than red stars.