Roger Cayrel (1925–2021) was a French astronomer internationally recognised as a pioneer in the study of stellar atmospheres. He has provided outstanding contributions in theoretical astrophysics, as well as in the understanding of the oldest stars and chemical evolution of the Milky Way. He was the first director of the Canada-France-Hawaii Telescope.
Reference: WGSBN Bulletin, 2023-02-27, Volume 3, Number 3, page 12