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The Hertzsprung-Russell diagram

by

P.Carril/Novapix

Reference

a-eto99-99000

Date

2007-03-02

The Hertzsprung-Russell diagram is named after the Danish astronomer Einar Hertzsprung (1873-1967) and the American astronomer Henry Norris Russell (1877 - 1957). At the beginning of the 20th century they independently noticed that red stars come in very different sizes, pioneering subsequent studies of stellar parameters (e.g., temperature, size and mass). In its basic version, this diagram plots stellar temperature (or colour) against brightness (or magnitude) and is therefore also referred to as the "colour-magnitude diagram". The position of a particular star in the diagram also provides information about its evolutionary stage (and age).