Alfred Harrison Joy

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Alfred Harrison Joy (born September 23, 1882 in Greenville , Illinois, † April 18, 1973 in Pasadena , California) was an American astronomer .

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After earning his bachelor's degree from Greenville College in Illinois and his master's degree in physics from Oberlin College , Joy taught for ten years at the American University of Beirut, where he became professor and director of the observatory there. During this time he established contacts with astronomers such as Henry Norris Russell while visiting various European and American observatories . The First World War prevented his return to Beirut from a trip to the USA in 1915, after which he worked at the Mount Wilson Observatory until his retirement in 1948 and remained scientifically active afterwards.

At the Mount Wilson Observatory, he initially dealt with solar observations, but in 1916 he turned to his later main field of work, star spectroscopy. In extensive observation projects, he and his colleagues measured radial speeds , determined the distance to stars using spectroscopic parallaxes, and examined variable stars such as Mira . He identified the class of T-Tauri stars . Based on his radial velocity measurements, he investigated the rotation and structure of the Milky Way .

Joy was President of the Astronomical Society of the Pacific in 1931 and 1939, and President of the American Astronomical Society from 1949 to 1952 . In 1944 he was elected to the National Academy of Sciences and in 1950 he received the Bruce Medal . In 2007 the asteroid (11769) Alfredjoy was named after him. The moon crater Joy is also named after him.

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Individual evidence

  1. ↑ Minor Planet Circ. 61267
personal data
SURNAME Joy, Alfred Harrison
BRIEF DESCRIPTION American astronomer
DATE OF BIRTH September 23, 1882
PLACE OF BIRTH Greenville, Illinois
DATE OF DEATH April 18, 1973
Place of death Pasadena, California