# The origin of the cratering asymmetry on Triton

## TL;DR

This study investigates the origins of Triton's cratering asymmetry by simulating impact distributions from various impactor sources, concluding that a mix dominated by heliocentric impactors best explains the observed crater pattern.

## Contribution

It introduces a dynamical approach using N-body simulations to analyze impactor sources and proposes a mixed impactor population model to explain Triton's crater asymmetry.

## Key findings

- Low-inclination Neptune-centric impactors concentrate craters on Triton's leading hemisphere.
- Heliocentric impactors produce too many craters on the trailing hemisphere.
- A mixed impactor population with 70% heliocentric impactors fits the observed crater distribution.

## Abstract

The source of impactors capable of producing the cratering asymmetry on Triton is open to debate. While hyperbolic comets are the likely source of impactors, the theoretically predicted crater distribution due to impacts from comets is incompatible with the observed crater distribution on Triton. In this study, we adopted a dynamical approach to investigate the crater distribution produced by three sources of impactors: Neptune-centric impactors on prograde, low-inclination orbits, Neptune-centric impactors on high-inclination orbits such as its irregular satellites, and heliocentric impactors with hyperbolic orbits. We employ N-body simulations which take into account the dynamics of the impacts. We found that none of the impactor sources alone are able to reconcile with the crater distribution on Triton. The crater distribution produced by a low-inclination Neptune-centric source is narrowly concentrated on Triton's leading hemisphere whereas the heliocentric impactors produce too many craters on the trailing hemisphere compared to the observed crater distribution. All three impactor populations produce craters on the trailing hemisphere of Triton. We derived the impact distribution of a mixed population of impactors using a Monte Carlo approach and found that if the population consists of mainly heliocentric impactors (70%), the resulting impact distribution fits the observed crater distribution on Triton's leading hemisphere well.