Russell (Hertzsprung-Russell diagram)

The Hertzsprung-Russell diagram (H-R diagram) is a vital tool in astronomy that illustrates the relationship between stars' luminosity (brightness) and their temperature (color). On this graph, stars are plotted with temperature on the horizontal axis and brightness on the vertical axis. It reveals patterns; for instance, most stars fall along the main sequence, where they spend most of their lives. The diagram helps astronomers classify stars, understand their life cycles, and study the evolution of galaxies. Essentially, it’s a map of stars that reveals important information about their characteristics and stages of development.