- Category : 1925-births
- Type : ME
- Profile : 1/3 - Investigating / Martyr
- Definition : Single
- Incarnation Cross : RAX Consciousness 4
French astronomer whose main interests were stellar atmospheres, galactic chemical evolution and metal-poor stars. 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.
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 had 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.
Since 1954, he had been married to the Italian astronomer Giusa de Strobel. Roger Cayrel died on 11 January 2021 at age 95 in Paris.