Date of Birth: 
Place of Birth: Bordeaux, Nouvelle-Aquitaine, France
About Roger Cayrel
- Roger Victor Emile Cayrel (born 4 December 1925, Bordeaux, France) is a French astronomer.
- His main interests are stellar atmospheres, galactic chemical evolution and metal-poor stars. He attended the Lycée Michel-Montaigne in Bordeaux and studied physics at the École normale supérieure and the Faculté des sciences de Paris. Beside his scientific work, he had a number of high-ranking posts in the management of science: director of the Canada-France-Hawaii Telescope (CFHT, 1974–1980), president of the IAU commission on stellar atmospheres (1973–1976) and head of the Bureau des Longitudes (1995–1996). Cayrel has been a corresponding member of the Académie des Sciences since 1988.
- He was awarded the Prix Jules Janssen of the Société astronomique de France (Astronomical Society of France), in 2001. Cayrel and his colleagues discovered thorium and uranium in the ultra-metal-poor halo star BPS CS31082-0001, which was named Cayrel's Star to honour him.
- From the thorium and uranium content, an age of 12.5 Billion years could be calculated. Since 1954, he has been married to the Italian astronomer Giusa de Strobel.
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