October 25: Henry Norris Russell

Henry Norris Russell

October 25, 1877 – February 18, 1957

Henry Norris Russell was an American astronomer who, along with Ejnar Hertzsprung, developed the Hertzsprung-Russell diagram (1910). In 1923, working with Frederick Saunders, he developed Russell-Saunders coupling which is also known as LS coupling.

Russell was born in 1877 in Oyster Bay, New York. He studied astronomy at Princeton University, obtaining his B.A. in 1897 and his doctorate in 1899, studying under Charles Augustus Young. From 1903 to 1905, he worked at the Cambridge Observatory with Arthur Robert Hinks as a research assistant of the Carnegie Institution and came under the strong influence of George Darwin.

He returned to Princeton to become an instructor in astronomy (1905-1908), assistant professor (1908-1911), professor (1911-1927) and research professor (1927-1947). He was also the director of the Princeton University Observatory from 1912 to 1947.

He co-wrote an influential two-volume textbook in 1927 with Raymond Smith Dugan and John Quincy Stewart: Astronomy: A Revision of Young’s Manual of Astronomy (Ginn & Co., Boston, 1926–27, 1938, 1945). This became the standard astronomy textbook for about two decades. There were two volumes: the first was The Solar System and the second was Astrophysics and Stellar Astronomy. The textbook popularized the idea that a star's properties (radius, surface temperature, luminosity, etc.) were largely determined by the star's mass and chemical composition, which became known as the Vogt-Russell theorem (including Hermann Vogt who independently discovered the result). Since a star's chemical composition gradually changes with age (usually in a non-homogeneous fashion), stellar evolution results.

The Lunar crater Russell is named in his honor.