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Glossary term: Luminosity class

Description: The brightness of a star depends on its temperature and physical size. Hotter stars are brighter, as are larger stars. Spectral type categorizes stars based on the appearance of their spectral lines. This roughly follows changes in temperature. The luminosity class categorises stars based on how bright they are compared to other stars of their spectral type. Stars on the main sequence burning hydrogen are classified as dwarfs. Above these lie (in order of increasing size and brightness) subgiants, giants, bright giants and supergiants. All of these are types of evolved stars that have finished burning hydrogen in their core. Metal poor subdwarfs are hydrogen burning stars with a low metal content that lie below the main sequence. Finally white dwarfs (stellar remnants) lie further still below the main sequence.

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Term and definition status: This term and its definition is still awaiting approval

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