Three Astronomy PhD students gave talks at the Division on Dynamical Astronomy’s 57th Annual meeting in June 2026 at the University of Chicago in Chicago, IL. Two of the central focuses of the meeting were the formation, migration, and dynamical evolution of planetary systems and their resonant chains, and the dynamics of globular clusters and their stellar streams.
This triptych of photos from the conference show Agustin Heron (top panel), Jordan Bruce (center panel), and Ryan LoRusso (bottom panel) presenting on their research, with the title slides for each of their presentations shown in the images below.
Agustin presented his research about how planetary size ordering could be used to constrain the initial conditions of planetary systems as well as their dynamical evolution at later stages. Using an extensive statistical analysis of super-Earths and sub-Neptunes in the Kepler catalog, Agustin showed that planetary systems with planets near mean-motion resonances—thought to represent young, dynamically cold systems—tend to exhibit greater size disorder than systems without planets near resonances, which are thought to be more mature and dynamically hot. A result that goes against the expectation that more mature and dynamically hotter systems should be more size-disordered.
The focus of Jordan’s talk was the dynamics of binary stars within the multiple populations of globular clusters, based on the research he has been conducting with his advisor Professor Enrico Vesperini. Jordan used the results from a suite of simulations to highlight how the unique dynamical environments of the multiple stellar populations can manifest within their binary populations in several key observable ways, and these binaries can then act as tracers of the early and long-term evolution of globular clusters.
During the final session, Ryan presented the results of N-body simulations which demonstrated that the dynamics of cold Neptunes can play a key role in shaping architectures of planetary systems. In those simulations, scattering from a few massive Mars-sized and smaller planetary embryos destabilize chains of cold Neptunes, with some Neptunes capable of being driven very close to their host stars due to secular chaos induced by the other, outer Neptunes in their systems. Such close approaches can produce planets similar to the emerging population of observed high-obliquity hot Neptunes.
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