Speaker: Dr. Chris O'Connor, Northwestern University
Abstract: Planetary systems are ubiquitous, but not eternal. In this two-part talk, I will describe recent work on long-term stellar evolutionary and dynamical processes that shape, transform, and destroy planets and planetary systems. In part one, I will introduce the extraordinary exoplanet WD1856b and summarize recent theoretical and observational progress, and enduring challenges, in understanding its formation and evolution. In part two, I will discuss the timely "breaking the chains" problem in exoplanet dynamics, which seeks an explanation for the declining prevalence of mean-motion resonances (MMRs) with age in compact planetary systems. I will describe a possible scenario for breaking the chains through planetesimal interactions and its implications about exoplanet architectures beyond the "ice line."