On Thursday, April 2, 2026, CRAL's young researcher Armand Leclerc was awarded the European Astrophysical Society (EAS) MERAC Prize for the best PhD thesis in Theoretical Astrophysics.
Awarded every two years by the MERAC Foundation—Mobilization of European Research in Astrophysics and Cosmology—the MERAC Prize aims to recognize and support young European astronomers by highlighting their work and providing financial support. This prestigious award recognizes Armand Leclerc’s work on developing a new topological description of waves and oscillations in stars, offering new perspectives in asteroseismology and helioseismology.
“I am very proud! It is a tremendous pleasure to have my thesis so highly recognized and celebrated by our community,” comments Armand Leclerc. “This award is an honor not only for me but also for my PhD supervisor at CRAL, Guillaume Laibe, and our collaborators at ENS de Lyon, without whom this entire project would not have been possible.”
Understanding the behavior of seismic waves that shake the surfaces of stars
Currently a postdoctoral researcher in Austria, Armand Leclerc defended his dissertation on October 13, 2025, at ENS de Lyon, on the topic: “Wave Topology for Asteroseismology.”
“My thesis work studies the seismic waves that propagate through stars—the tremors of stars. The field of asteroseismology interprets these vibrations that we see agitating their surfaces to deduce their hidden internal structure, just as we do on Earth,” he explains. “The core of my thesis is to examine these waves through the lens of topological physics, which was originally developed to shed light on certain phenomena in quantum physics; here, to obtain new results on stellar seismic waves and a new understanding of some of their behaviors. This new perspective has borne fruit, offering new ways to harness stellar seismic waves to deduce as-yet-unmeasured properties of the interiors of stars, particularly our Sun.”
Expanding the Capabilities of Seismology
When it comes to the next steps, Armand Leclerc is full of enthusiasm and intends to keep his eyes on the stars: “There is still so much to learn and understand about the stars! I am currently working in Austria at the Institute of Science and Technology Austria as a postdoctoral researcher with Dr. Lisa Bugnet to develop capabilities in seismology so that it can provide insights into the magnetic activity of stars. I will continue my research at the interface between quantum physics and stellar physics.”
In honour of the award he has won, Armand Leclerc will, alongside the five other recipients of the 2026 EAS Awards, deliver a plenary lecture at the annual meeting of the European Astronomical Society, to be held in Lausanne, Switzerland, from June 29 to July 3, 2026.