Hertzsprung-Russelldiagram

Hertz·sprung-Rus·sell diagram (hĕrts'sprŭng-rŭsʹəl) n.

A graph of the absolute magnitude of stars plotted against their surface temperature or color, used in the study of stellar evolution.

  [After Ejnar Hertzsprung (1873-1967), Danish astronomer, and Russell, Henry Norris.]

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