BornHalle, Germany, 6 July 1883
DiedBonn, (Germany), 28 May 1969
Arnold Kohlschütter and Walter Adams found subtle criteria that could distinguish ordinary giants from dwarf stars.
Kohlschütter was educated at Göttingen University, a student of Karl Schwarzschild. He spent 3 years at Mount Wilson Observatory, California, from 1911 to 1914. There he cooperated with Adams in the work that led to a new method for determining the distances to stars.
Kohlschütter and Adams examined the spectra of stars with both large and small parallaxes, but similar apparent magnitudes. The stars with smaller parallaxes were necessarily more luminous. The two Mount Wilson spectroscopists found differences in the absorption-line strength ratios between the two sets of stars – even within the same spectral class. Once calibrated using stars of known distance, these differences could be observed in stars without measured parallax in order to determine their distances. The method refined the technique known as sp...