# OSSOS IXX: Testing Early Solar System Dynamical Models using OSSOS Centaur Detections

## TL;DR

This study tests early Solar System models by comparing predicted and observed Centaur populations and orbital distributions, finding a strong match and providing population estimates for various small body reservoirs.

## Contribution

It introduces a dynamical model with grainy Neptune migration that accurately predicts Centaur distributions and populations, validated against OSSOS survey data.

## Key findings

- Excellent match between model predictions and OSSOS Centaur observations.
- Estimated 21,000+/-8,000 Centaurs with D>10 km.
- Predicted and observed number of Centaurs with specific orbital parameters are consistent.

## Abstract

We use published models of the early Solar System evolution with a slow, long-range and grainy migration of Neptune to predict the orbital element distributions and the number of modern-day Centaurs. The model distributions are biased by the OSSOS survey simulator and compared with the OSSOS Centaur detections. We find an excellent match to the observed orbital distribution, including the wide range of orbital inclinations which was the most troublesome characteristic to fit in previous models. A dynamical model, in which the original population of outer disk planetesimals was calibrated from Jupiter Trojans, is used to predict that OSSOS should detect 11+/-4 Centaurs with semimajor axis a<30 au, perihelion distance q>7.5 au and diameter D>10 km (absolute magnitude H_r<13.7 for a 6% albedo). This is consistent with 15 actual OSSOS Centaur detections with H_r<13.7. The population of Centaurs is estimated to be 21,000+/-8,000 for D>10 km. The inner scattered disk at 50<a<200 au should contain (2.0+/-0.8)x10^7 D>10 km bodies and the Oort cloud should contain (5.0+/-1.9)x10^8 D>10 km comets. Population estimates for different diameter cutoffs can be obtained from the size distribution of Jupiter Trojans (N(>D) proportional to D^(-2.1) for 5<D<100 km). We discuss model predictions for the Large Synoptic Survey Telescope observations of Centaurs.