Alfred Harrison Joy (September 23, 1882 in Greenville, Illinois – April 18, 1973 in Pasadena, California) was an astronomer best known for his work on stellar distances, the radial motion of stars, and variable stars.
Joy, a prominent clothing merchant in Greenville and one-time mayor of the town.
[2] After graduating, Joy went on to work at the American University of Beirut in the Syrian Protestant College as a professor of astronomy and the director of the observatory.
There, he and his colleagues ascertained the spectral type, absolute magnitude, and stellar distance of over 5,000 stars.
Joy also initially defined the T-Tauri type star.