Modeling and Analysis of Main-Belt Asteroidal Dust Flux and Velocity Distribution at Inner Planets

TL;DR

This study models the flux and velocity distribution of asteroidal dust impacting inner planets using N-body simulations, providing insights into impact processes and surface modifications.

Contribution

It offers a detailed dynamical analysis of asteroid-derived dust fluxes and impact velocities, calibrated against existing models, with implications for planetary surface processes.

Findings

Fluxes agree with existing models within 0.1 orders of magnitude.

Low-eccentricity grains dominate dust flux; high-eccentricity grains influence impact velocities.

Impact velocity distributions show decoupling between flux and impact speed.

Abstract

Interplanetary dust in the inner solar system originates from multiple sources, including short-period comets and main-belt asteroids. In this work, we focus specifically on the dynamical evolution of asteroid-derived dust using N-body simulations that incorporates solar gravity, planetary perturbations, radiation pressure, Poynting-Robertson drag and solar wind forces. We quantify dust fluxes for Mars, Venus and Mercury across an important mass range, which are essential inputs for ablation process on Mars/Venus and for contributing in the impact process on Mercury. We have also derived impact velocity distributions and compared with existing literature. In addition, we examine how close-encounter velocities depend on the orbital elements linking dust energetics directly to the orbital architecture of the dust population. Our results show that the calibrated asteroidal flux agrees excellently with the scaled Gr\"un model for Mars (0.04 orders of magnitude offset) and Venus (0.09 orders), and with the M\"uller (2002) model for Mercury (0.04 orders). The velocity distributions reveal a decoupling between flux and impact velocity: low-eccentricity grains dominate the flux, while high-eccentricity grains control the high-velocity tail. These findings have direct implications covering: (i) For atmosphere-less bodies like Mercury, the high-velocity tail affects impact processes and exosphere generation; (ii) For Mars and Venus, the flux-dominated low-velocity population determines meteoroid ablation rates and metal layer formation; (iii) Our calibrated fluxes provide inputs for comparison with future observations from different missions and also, for modeling impact-driven surface modification across the inner solar system.