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Title: Mercury’s Chaotic Secular Evolution as a Subdiffusive Process
Abstract Mercury’s orbit can destabilize, generally resulting in a collision with either Venus or the Sun. Chaotic evolution can causeg1to decrease to the approximately constant value ofg5and create a resonance. Previous work has approximated the variation ing1as stochastic diffusion, which leads to a phenomological model that can reproduce the Mercury instability statistics of secular andN-body models on timescales longer than 10 Gyr. Here we show that the diffusive model significantly underpredicts the Mercury instability probability on timescales less than 5 Gyr, the remaining lifespan of the solar system. This is becauseg1exhibits larger variations on short timescales than the diffusive model would suggest. To better model the variations on short timescales, we build a new subdiffusive phenomological model forg1. Subdiffusion is similar to diffusion but exhibits larger displacements on short timescales and smaller displacements on long timescales. We choose model parameters based on the behavior of theg1trajectories in theN-body simulations, leading to a tuned model that can reproduce Mercury instability statistics from 1–40 Gyr. This work motivates fundamental questions in solar system dynamics: why does subdiffusion better approximate the variation ing1than standard diffusion? Why is there an upper bound ong1, but not a lower bound that would prevent it from reachingg5?  more » « less
Award ID(s):
2054306
PAR ID:
10539456
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
American Astronomical Society
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
967
Issue:
2
ISSN:
0004-637X
Page Range / eLocation ID:
121
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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