Jean Claude Barthélemy Dufay (July 18, 1896–November 6, 1967) was a French

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...

. During his career he studied nebulae,

interstellar matter In astronomy, the interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstellar s ...

, the night sky and cometary physics. In 1925, while working in collaboration with

Jean Cabannes Jean Cabannes (born 12 August 1885 – died 31 October 1959) was a French physicist specialising in optics. Education and career Cabannes studied at the Lycée de Nice and entered the École Normale Supérieure in 1906. From 1910 to 1914, Caba ...

, he computed the altitude of the Earth's

ozone layer The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains a high concentration of ozone (O3) in relation to other parts of the atmosphere, although still small in rela ...

. He was named the honorary director of the

Lyon Observatory Lyon Observatory is located in Saint-Genis-Laval, a commune in the Rhône department in eastern France, near Lyon. Founded in 1878, the entire facility was listed as a historical site on May 9, 2007. In 1867, Paris astronomer Charles André reque ...

. He became a member of the

French Academy of Sciences The French Academy of Sciences (French: ''Académie des sciences'') is a learned society, founded in 1666 by Louis XIV of France, Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French Scientific me ...

in 1963. His undergrad was completed in 1913 and his Ph.D. in 1928 under

Charles Fabry Maurice Paul Auguste Charles Fabry (; 11 June 1867 – 11 December 1945) was a French physicist. Life Fabry graduated from the École Polytechnique in Paris and received his doctorate from the University of Paris in 1892, for his work on i ...

and

. In between he served (and was wounded) in World War I and taught. Dufay was appointed at the

since 1929 and stayed there until his retirement in 1966. He was awarded the

Valz Prize The Valz Prize ''(Prix Valz)'' was awarded by the French Academy of Sciences, from 1877 through 1970, to honor advances in astronomy. History The Valz Prize was established in June 1874 when the widow of astronomer Benjamin Valz, Marie Madeleine J ...

by the

in 1932 for his work on astronomical photometry. The crater Dufay on the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

is named after him.

Bibliography

* Dufay, Jean. ''Nébuleuses galactiques et matière interstellaire'' (Albin Michel, 1957). * Dufay, Jean. ''Introduction à l'astrophysique. Les étoiles'' (Armand Colin, 1961).An English translation, by

Owen Gingerich Owen Jay Gingerich (; born 1930) is professor emeritus of astronomy and of the history of science at Harvard University and a senior astronomer emeritus at the Smithsonian Astrophysical Observatory. In addition to his research and teaching, he has ...

, was published as
Introduction to Astrophysics: The Stars
' (Dover Books, 1964).

References

1896 births 1967 deaths 20th-century French astronomers Members of the French Academy of Sciences {{france-astronomer-stub