Catalogue · 1943 CE

Yerkes (MKK) Classification

History of Astronomy

About the catalogue

The two-dimensional classification developed by Morgan, Keenan, and Kellman at Yerkes Observatory, adding a luminosity class (I–V) to the Harvard temperature type. It distinguishes giants from dwarfs and is the modern standard for spectral classification.

Knowledge connections

Part ofModern Astronomy

Sources & references

The primary and reference sources this topic draws on.

NASA ADSNASA Astrophysics Data System
Bibliographic index of peer-reviewed astronomy and astrophysics literature.
BritannicaEncyclopaedia Britannica
General reference for the history of astronomy, biographies, and cultural context.