Hertzsprung–Russell diagram

Frae Wikipedia
Lowp tae: navigation, rake
An HR diagram shawin mony well kent starns in the Milky Way galaxy.

The Hertzsprung–Russell diagram, abbreviatit H–R diagram or HRD, is a scatter graph o starns shawin the relationship atween the starns' absolute magnitudes or luminosities versus thair spectral clessifications or effective temperaturs.