What does the color of a star signify?

The color of a star is directly related to its surface temperature. Stars emit light in various colors based on their temperatures, which can be understood through the concept of blackbody radiation. Hotter stars tend to emit light that appears blue or white, while cooler stars emit light that appears red or orange. The temperature can be measured in Kelvin, and different temperature ranges correspond to specific colors.

For instance, a star with a surface temperature between 7,500 to 10,000 Kelvin would appear white or blue, while a star with a surface temperature below 3,500 Kelvin would appear red. This relationship allows astronomers to determine a star's temperature by observing its color, making it a critical factor in understanding stellar characteristics and classification. The other options focus on different aspects, such as brightness, which is influenced by both distance and size, but does not directly correlate with color. Similarly, while distance and size are important attributes of stars, they do not influence the color that is indicative solely of surface temperature.