Sky science
Hertzsprung-Russell Diagram
Direct answer
Hertzsprung-Russell Diagram: A Hertzsprung-Russell Diagram plots stellar luminosity or absolute magnitude against temperature, color, or spectral type.
It maps stars by brightness and temperature.
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At a glance
- Found in
- Astronomy & Skywatching
- Related
- Stellar Spectrum, Spectral Type, Main Sequence, Protostar
It maps stars by brightness and temperature.
A scientific orientation to scale, light, or motion; the article supplies the precise definition.
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The story behind Hertzsprung-Russell Diagram
Ejnar Hertzsprung and Henry Norris Russell independently developed related diagrams in the early twentieth century.
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Why Hertzsprung-Russell Diagram matters
Hertzsprung-Russell Diagram exposes the main sequence, giant branches, and white-dwarf region.
How to read Hertzsprung-Russell Diagram
Check both axes because astronomical temperature often runs hot-to-cool from left to right.
Where readings of Hertzsprung-Russell Diagram go wrong
A star moves on the diagram through evolution, not through physical space.
Sources and editorial method
Research references used for this entry include:
- NASA Science: Stars - NASA overview of stellar birth, main-sequence evolution, giant phases, remnants, and supernovae.
- NASA Science: Universe Glossary - NASA definitions for common stellar, galactic, orbital, and high-energy astronomy terms.
- Source
- The Great Almanac Dictionary
- Category
- Astronomy & Skywatching
- Last updated
- 2026-09-26
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Common questions
What is a Hertzsprung-Russell Diagram?
A Hertzsprung-Russell Diagram plots stellar luminosity or absolute magnitude against temperature, color, or spectral type.
What do people get wrong about a Hertzsprung-Russell Diagram?
A star moves on the diagram through evolution, not through physical space.
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