How are stars classified?
When a star first forms, the mass it collects through gravity determines the star’s color and brightness. Low mass stars are cooler, dimmer, and redder. Highly massive stars are hotter, brighter, and bluer. As an analogy, imagine the heating elements of a toaster. When electricity starts to pulse through the coils, those elements glow a deep brownish red. Very quickly, they warm to bright orange. If electricity were to continue increasing in strength, those heating elements would soon become bright yellow, then white. If the heat doesn’t melt the elements, the increasing temperature would move the color toward a brilliant white, tinged with blue and violet. The color of a star is directly related to the temperature of its surface. As the temperature at the surface of any object increases, the peak frequency of energy output increases along the spectrum from red toward the blue and violet. Stars are nuclear furnaces. At their cores, sustained chain reactions of hydrogen fusion persist u
