Final answer:
The Hertzsprung-Russell diagram (H-R diagram) categorizes stars based on luminosity and surface temperature, with most stars residing on the main sequence. Other areas of the diagram illustrate the evolutionary stages of stars, including red giants, supergiants, and white dwarfs.
Step-by-step explanation:
The Hertzsprung-Russell diagram, or H-R diagram, is a crucial tool in the field of astrophysics that links stellar luminosity to surface temperature. Most stars, approximately 90%, appear along the main sequence of this diagram. A star's position on the main sequence is determined by its mass, with high-mass stars being hotter and more luminous compared to low-mass stars. When stars exhaust their nuclear fuel, they leave the main sequence to enter the later stages of their evolution, becoming red giants or supergiants, and ultimately white dwarfs.
Other major regions on the H-R diagram include areas where you can find super giants, which are very bright and have cool surfaces, lying towards the upper right of the diagram. White dwarfs are hot but dim and are found in the lower left of the diagram. Stars like our Sun evolve through these areas after spending the majority of their life in the main sequence.