Wine and Cheese Spring 2023

This page records the schedule, titles and abstracts of the JHU/STScI CAS Astrophysics Wine & Cheese Series in Spring 2023.

Wine and Cheese sessions with one speaker will have a 50 minute talk with 10 minutes for questions. Sessions with two speakers will have two 25 minute talks, each with 5 minutes for questions. Sessions in the Graduate Student Series will have three 15 minute talks, each with 5 minutes for questions.

30 January

Matt Clement (JHU-APL)

The Early Secular Evolution of the Outer Solar System and the Present State of the Nice Model
In the current consensus dynamical evolutionary hypothesis for the solar system, after forming in a compact configuration of circular orbits, the giant planets acquire their modern dynamical configuration through an episode of orbital instability. Over the past two decades, numerical simulations of the so-called Nice Model have been successfully leveraged to explain numerous peculiar solar system qualities. In particular, the orbital distributions of small bodies (e.g.: asteroids, Kuiper belt objects, irregular satellites and outer solar system trojans) provide strong observational constraints that no other proposed model is capable of satisfying. I will review the current state of the Nice Model, and highlight a collection of systematic issues identified in past studies that have motivated my research activities as a postdoc. While simulations in classic investigations overestimated the inner asteroid belt’s high inclination population by several orders of magnitude (i.e.: they create stable orbits that are not observed today), I will show how Jupiter and Saturn’s precise approach to their modern orbits induces a corresponding cycling of resonances in the belt that removes these objects. An additional constraint on instability simulations comes from Jupiter's fifth eccentric eigenmode, which is an important driver of the solar system’s global evolution. Starting from commonly-assumed near-circular orbits, the present-day magnitude of this mode in Jupiter’s eccentricity vector is significantly outside the range of numerically generated outcomes. I will present new results motivated by modern hydrodynamical simulations of the giant planets' evolution within the primordial gaseous disk that consider the possibility of Jupiter and Saturn emerging from the nebular gas locked in 2:1 resonance with non-zero eccentricities. I will show that, in such a scenario, the modern Jupiter-Saturn system represents a typical simulation outcome. Finally, I will highlight the survivability of the giant planets’ regular satellites (namely those of Jupiter and Uranus) as an outstanding problem, and discuss the potential implications of this shortcoming.