Final answer:
The H-R diagram compares a star's absolute magnitude and temperature, plotting these attributes to reflect a star's position and evolutionary stage within the Main Sequence and beyond.
Step-by-step explanation:
The H-R diagram is a comparison between star's absolute magnitude (luminosity) and temperature. The Hertzsprung-Russell diagram, commonly referred to as the H-R diagram, is an important tool in astronomy that plots stars according to their luminosity and temperature. On this diagram, temperature typically appears on the horizontal axis and increases toward the left, while luminosity goes on the vertical axis, increasing upward. Most stars fall along the Main Sequence, stretching diagonally across the diagram from high temperature and high luminosity to cooler, dimmer stars. The position of a star on the Main Sequence correlates with its mass, with high-mass stars being hotter and more luminous than low-mass stars. As a star evolves, it may move across the H-R diagram, with changes in temperature and luminosity reflecting the different stages of its life cycle.