Stellar Classification And The H-r Diagram, The Main Sequence, Giant Stars, The H-r Diagram And Stellar EvolutionThe nature of the H-R diagram
A Hertzsprung-Russell diagram, or H-R diagram, is a graph of stellar temperatures (plotted on the horizontal axis) and luminosities, or brightnesses (plotted on the vertical axis). H-R diagrams are valuable because they reveal important information about the stars plotted on them. After constructing an H-R diagram for a group of stars, an astronomer can make estimates of many important stellar properties including diameter, mass, age, and evolutionary state. Our understanding of the processes at work in the stars depends on knowing these parameters, so H-R diagrams have been essential tools in twentieth-century astronomical research.
Figure 1 shows all the important features of the H-R diagram. The stars fall into several relatively narrow strips which W. W. Morgan, another famous classifier of stellar spectra, called luminosity classes. Luminosity classes are denoted by Roman numerals.
- Hertzsprung-Russell Diagram - Stellar Classification And The H-r Diagram
- Hertzsprung-Russell Diagram - The Main Sequence
- Hertzsprung-Russell Diagram - Giant Stars
- Hertzsprung-Russell Diagram - The H-r Diagram And Stellar Evolution
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