The Canadian Institute for Theoretical Astrophysics (CITA) is proud to announce that postdoctoral fellow Dr. Sam Hadden is the recipient of the 2025-26 Vincent and Beatrice Tremaine Postdoctoral Fellowship.
The Vincent and Beatrice Tremaine Postdoctoral Fellowship was established by Vincent Tremaine in memory of Beatrice D. Tremaine. The fellowship honours her lifelong interest in mathematics, science, and learning. It is awarded specifically to highlight outstanding scholars who use applied mathematics and mathematical models to advance the field of astrophysics.
Dr. Hadden’s selection for this prestigious fellowship perfectly reflects the award’s core mission. As an expert in planetary dynamics, Sam’s analytic and numerical work focuses on exoplanet observations such as transit timing and radial velocity measurements. By developing sophisticated mathematical frameworks, he decodes complex orbital phenomena—such as mean-motion resonances and chaos—to understand the architecture and evolution of planetary systems beyond our solar system.
A cornerstone of his research involves Transit Timing Variations (TTVs). When planets orbit close to one another, their mutual gravitational tugs cause them to transit their host star slightly early or slightly late. By applying his mathematical models to these timing variations, Dr. Hadden is able to “weigh” exoplanets and measure their orbital properties with incredible precision.
Recently, Dr. Hadden has published several co-authored or single-author papers that explore fundamental questions about dynamical interactions or propose answers to contemporary questions about planetary systems. In his paper “Free Floating or Merely Detached?” published in the Astrophysical Journal, he used advanced simulations to propose that planet-planet scattering could produce a population of planets on wide and eccentric orbits that might be interpreted observationally as free-floating rogue planets. In another pivotal paper, “Rattle-and-Break: the Impact of Planetesimal Scattering on Super-Earth Resonant Chains,” he showed how highly structured planetary systems can be disassembled over time by the scattering of small planetesimals.
“Dr. Hadden’s ability to translate the chaotic and intricate gravitational tug-of-war of exoplanets into elegant, solvable mathematical models makes him an ideal recipient for the Tremaine Fellowship,” says Shantanu Basu, Interim Director of CITA. “His work proves that applied mathematics and numerical simulations remain some of our most powerful tools for understanding the cosmos.”
Please join us in congratulating Sam Hadden on this achievement and his continued contributions to theoretical astrophysics!
(To learn more about Dr. Hadden’s research on planetary dynamics, visit his research page at shadden.github.io/research/).