Collective Gravity of Minor Planets In The Outer Solar System

Graduate Thesis Or Dissertation

Citations

Citeable URL: https://scholar.colorado.edu/concern/graduate_thesis_or_dissertations/db78td27z

Abstract

Axisymmetric disks of eccentric Kepler orbits are susceptible to the inclination instability, an out-of-plane buckling characterized by exponentially growing inclinations, decreasing eccentricities, and clustering in argument of periapsis. Observations of trans-Neptunian Objects (TNOs), minor planets orbiting around and beyond the orbit of Neptune, reveal a similar structure. Here we explore if the inclination instability could explain these observations if it occurred in the young Solar System within Neptune's primordial Scattered Disk. We describe the mechanism governing the instability using a two-orbit mutual torque model, and we derive an expression for the timescale of the instability as a function of disk mass for realistic astrophysical disks. We find that the inclination instability can occur in disks modelled after the Scattered Disk in the outer Solar System, but we find that precession induced in the outer Solar System by the quadrupole potential of the giant planets can suppress the instability if the total disk mass is not large enough. We find that the primordial Scattered Disk would need to host ≳ 20 Earth masses of material in order to undergo the inclination instability. Finally, we find that the post-inclination instability disk evolves into a lopsided, ϖ -clustered state which can explain similar observations of the TNOs.

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