Corinne Charbonnel is a full professor of astrophysics at the University of Geneva. This is not a matter of course, as she was only the second woman ever to be appointed to a professorship at the Astronomy Department of the University of Geneva. The 57-year-old scientist is a strong advocate for young female researchers, among other things as a mentor.
Corinne Charbonnel is an astrophysicist. One focus of her research concerns the question of how stars evolve. She studies the processes that take place in stars when light chemical elements such as hydrogen or helium fuse to form heavier atoms and then escape into space and enrich the Galaxy (so-called nucleosynthesis). The scientist computes stellar evolution models that include sophisticated hydrodynamical mechanisms, and compares model predictions for the abundances of chemical elements at the stellar surface to spectroscopic measurements in stars over the Galaxy and beyond. In this way, she gains information about the substances that the stars are made of or about the atomic nuclei that are produced in the celestial bodies by means of nucleosynthesis.
"My field of research needs expertise in physics and magneto-hydrodynamics, but also the know-how about numerical models for computer-based calculations," says Corinne Charbonnel. For her research, the 57-year-old scientist needs observation data from very large telescopes such as those stationed in Chili or, for example, on the European Space Agency's GAIA research satellite launched in 2013. Her main area of work, however, is in the field of theory. In other words, she designs explanatory models for stars and star clusters that are later tested by means of observations and found to be correct or false.
The "helium-3 problem" solved
If you ask Corinne Charbonnel about her greatest scientific success in her now 30-year career as an astrophysicist, she answers with a beautiful story. It begins in July 1969, when Neil Armstrong and Buzz Aldrin became the first humans to land on the moon. The astronauts conducted various experiments on the moon. One of them was invented by Johannes Geiss, a physics professor from Bern. It consisted of an aluminium foil that the astronauts stretched out to catch the particles of the solar wind. Later, on Earth, it was determined the abundance ratios of the particles the aluminium foil had collected.
The studies of the solar wind later led to an unsolved scientific question that became known as the "helium-3 problem". Helium-3 stands for that rare helium isotope that has only one instead of two neutrons in the atomic nucleus. The "helium-3 problem" is the contradiction, discussed for decades, that there is less helium-3 in the Milky Way than would be expected on the basis of the classical theory of stellar evolution and Big Bang nucleosynthesis. Corinne Charbonnel and her doctoral student at the time, Nadège Lagarde, provided the key to resolving this contradiction with their research in 2009, when they included in their stellar models the double-diffusive instability, a well-known process in oceanography. "I am proud that together with Nadège we were able to propose the now accepted solution to this long-lasted problem which was raised by the first experiments carried by men on the Moon" says Corinne Charbonnel.
Advancement of women "absolutely necessary“
Nadège Lagarde now works at the French research organization 'Centre National de la recherche scientifique' (CNRS). Corinne Charbonnel, who was also born in France, also holds a CNRS position as senior researcher. However, she is on leave from this to work as an astronomy professor at the University of Geneva. The scientist has her office at the 'Observatory' in Versoix, northeast of Geneva. Corinne Charbonnel is currently supervising two male doctoral students, one from Russia and one from India, as well as a female Master's student from Colombia. "We are very international here, partly because we do not have enough Swiss students in our field, and also because international collaboration is the essence of science," Charbonnel comments.
If a female applicant and a male applicant for a research position are equally well qualified, Corinne Charbonnel decides in favor of the woman. She also provides support for young women through two mentoring programs offered by the Equal Opportunities Office of the University of Geneva for female doctoral students, postdocs, and promising junior women in academia. "The academic system in Switzerland is very hierarchical, to name just one of the problems we discuss in the mentoring meetings. Also, women (as well as men) scientists today are under enormous pressure to publish scientific papers and obtain funding. Another topic of discussion with the women is the upcoming career steps," says Corinne Charbonnel and adds: "The targeted promotion of women is still absolutely necessary today, even for those whose academic careers are already advanced."
Astrophysics instead of monkey science
Corinne Charbonnel's academic career was not set in stone from the start either. Her grandparents were assembly line workers in a large industry, her parents had a television and electronics business. "All the women of my family and friends of my parents were working," says Charbonnel, looking back on her youth in the central French town of Clermont-Ferrand. She was the first woman in her family to pursue an academic career. She was interested in primatology (the study of apes) and philosophy, but eventually studied mathematics and physics in Toulouse. There she completed her doctoral thesis in Astrophysics on lithium formation in stars supervised by Prof. Sylvie Vauclair in 1992. She then did research in Geneva, Toulouse, Seattle, Baltimore, and Munich. In 2002, she joined the University of Geneva as a lecturer. She became an associate professor in 2010 and a full professor in 2021.
Corinne Charbonnel has received various awards for her scientific work. "I am actually much more pleased than these awards when one of my former students gets a permanent position," emphasizes the Geneva scientist. Many academics live in temporary positions and thus in precarious circumstances. To achieve the goal of a permanent position, she advises young academics to expand their network and actively present their results to the scientific community, e.g. on the occasion of conferences.
Family of physicists
Corinne Charbonnel was 29 years old when she got her first permanent position at CNRS, and 45 years old when she got appointed professor in Switzerland in 2010, becoming the second woman ever to become a professor at the Department of Astronomy of the University of Geneva. There is another special feature: namely that not only she, but also her husband Daniel Schaerer is a professor of astrophysics at the University of Geneva. "This is a fantastic constellation," says Corinne Charbonnel, "we often have similar problems and can help each other. We also managed to coordinate when it came to who watches the children," Corinne Charbonnel looks back. The two sons are now grown up and studying in Paris, one theoretical physics, the other physics and chemistry. The apple, it is obvious, does not fall far from the tree.
Author: Benedikt Vogel
Portrait #12 of Women in science in the fields of MAP (2021/2022)