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.
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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.
