Postdoctoral Research Associate, Astrophysics Group
Department of Applied Mathematics and Theoretical Physics, University of Cambridge
I am a theoretical astrophysicist working on various problems in orbital dynamics and disk hydrodynamics, using a combination of analytical modelling, semi-analytical calculations, and large-scale numerical simulations.
Research
My work sits at the intersection of orbital dynamics and gas dynamics — the question of how gravity and gas together sculpt the architectures we observe, from compact multi-planet systems to the inner regions of AGN disks.
Planet–planet scattering, collisions and mergers, the spins and obliquities of merger remnants, and how resonant chains are broken.
Figure: How long a planetary system survives before going unstable, versus the initial spacing of its orbits in Hill radii, for four planet masses; the timescale grows with spacing above Ksyn, and systems become stable beyond Kcrit. From Li, Rodet & Lai (2024).
Eccentric modes and instabilities that form rings without planets, secular resonances that excite planetary eccentricity, and warped disks from the linear regime through to breaking.
Movie: Concentric rings emerging through an eccentric cooling instability, with no planet present. From Li, Dempsey, Li & Li (2021).
How stellar-mass black holes embedded in AGN disks meet, capture one another, and harden into merging binaries.
Movie: Two black holes meet inside their Hill sphere (dashed circle); the collision of their circum-single disks drains orbital energy and leaves the pair bound. From Li, Dempsey, Li, Lai & Li (2023).
Recent