Yvette J. Cuny




We sadly announce the passing of Yvette Cuny which occured on 6 April 2020 at the age of 94.
Yvette Cuny started her research at the Service d’Astrophysique de l’Observatoire de Meudon, then led by Jean-Claude Pecker. She confronted the then new problem raised by the first spectroscopic observations of the solar chromosphere, a piece of atmosphere above the photosphere, rather “warm” (around 10⁴ K) and very far from LTE. Several groups were working on this issue in the USA (Harvard, Boulder, Indiana University), and Yvette’s first task was to check that the NLTE numerical solutions of the coupled equations (statistical equilibrium, radiative transfer) from the different methods (and computers!) involved provided similar results. Yvette Cuny managed to implement her own differential method, based on Feautrier’s work. (We refer the reader to her thesis “Détermination exacte de la structure stationnaire d'une atmosphère d'hydrogène. Problème hors de l'équilibre thermodynamique local”) published in 1967, in the Annales d’Astrophysique).

On the basis of her first results, Yvette Cuny participated to the Bildelberg conference which led to the Bildelberg Reference Atmosphere, and then established with O. Gingerich, R.W. Noyes, and W. Kalkofen, the “Harvard-Smithsonian Reference Atmosphere” (HSRA).

Later, Yvette Cuny addressed various problems concerning the chromosphere, in particular the disagreement between densities derived from “on-disk” and “off-disk” (eclipse ) observations.
Yvette Cuny leaves us the memory of a pioneer in NLTE radiative transfer and a tenacious and smiling scientist.

Past affiliation(s) within the IAU

  • Past Organizing Committee Member of Commission 36 Theory of Stellar Atmospheres (1991-1994)
  • Past Member of Division E Sun and Heliosphere
  • Past Member of Division G Stars and Stellar Physics
  • Past Member of Commission 36 Theory of Stellar Atmospheres (until 2015)
  • Past Member of Division IV Stars (until 2012)

Search individual members


IAU GA 2021 Business Sessions

Strategic Plan

IAU Strategic Plan 2020–2030

Strategic Plan

IAU Code of Conduct

Code of Conduct

Symposia and Meetings


IAU General Assembly 2022



How to Become a Member

IAU Catalyst

Latest Catalyst

IAU e-Newsletter
Volume 2021 n° 6

Latest e-Newsletter

Subscribe to the e-Newsletter


IAU Office of Astronomy for Development

Office for Astronomy Development

IAU Office for Young Astronomers

Office for Young Astronomers

IAU Office for Astronomy Outreach

Office for Astronomy Outreach

IAU Office of Astronomy for Education

Office of Astronomy for Education

International School for Young Astronomers

International School for Young Astronomers

WG Small Bodies Nomenclature Bulletins

WG Small Bodies Nomenclature Bulletins