OSSOS XV: PROBING THE DISTANT SOLAR SYSTEM WITH OBSERVED SCATTERING TNOS

Area of Science:

• Planetary Science
• Astronomy
• Astrophysics
• Solar System Dynamics

Background:

• Most trans-Neptunian objects (TNOs) scattering off giant planets align with classical Kuiper Belt origins.
• A small fraction of scattering TNOs exhibit unusually high inclinations (i > 45°), inconsistent with this origin.
• These outliers have been hypothesized as Oort Cloud interlopers or evidence of an undiscovered planet.

Purpose of the Study:

• To test the Oort Cloud and undiscovered planet hypotheses for highly inclined scattering TNOs.
• To analyze N-body simulations against observational data from the Outer Solar Systems Origins Survey.

Main Methods:

• Utilized N-body simulations to model the orbital evolution of TNOs.
• Compared simulation results with observational data of 69 centaurs and scattering TNOs.
• Accounted for observational biases in the analysis of TNO orbital distributions.

Main Results:

• Confirmed that classical Kuiper Belt objects alone cannot account for observed high-inclination scatterers.
• Both Oort Cloud interlopers and a distant 5 Earth-mass planet can generate observable highly inclined scatterers.
• A distant planet model replicates the fraction of highly inclined scatterers but shows a more excited inclination distribution than observed.

Conclusions:

• The Oort Cloud hypothesis requires enrichment mechanisms (e.g., galactic migration) to match observed numbers.
• A distant planet, while plausible, requires further refinement to fully match the observed inclination distribution and longitudinal asymmetry.
• The orbital distribution of scattering TNOs serves as a powerful constraint for understanding the unobserved outer solar system.