The Detectability of Lunar-Origin Asteroids in the LSST Era

TL;DR

This paper investigates the population, orbital evolution, and detectability of lunar-origin asteroids (LOAs) using simulations, predicting about 6 LOAs could be detected annually by the LSST, with unique approach directions and velocities.

Contribution

It combines lunar ejecta modeling with orbital simulations to estimate LOA population and detection prospects, providing new insights into their characteristics and survey strategies.

Findings

Approximately 6 LOAs (D > 5 m) per year detectable by LSST.

LOAs tend to approach from sunward and anti-sunward directions.

LOAs have lower encounter velocities than typical NEAs.

Abstract

While most near-Earth asteroids (NEAs) are thought to originate from the main belt, recent discoveries have suggested the existence of a lunar-derived NEA population, such as the asteroids Kamo'oalewa and 2024 PT5. These objects may hold key clues to the dynamical evolution of NEAs and the recent impact history of the Earth-Moon system. However, the population, distribution, and dynamical characteristics of these Lunar-Origin Asteroids (LOAs) remain poorly constrained. By combining the lunar ejecta production with N-body orbital simulations of the ejecta, we investigate their orbital evolution in the past millions of years and the current LOA population, revealing their significant potential for detection by future surveys. Specifically for the Vera C. Rubin Observatory's upcoming Legacy Survey of Space and Time (LSST), we predict an average detection rate of about 6 LOAs (with D > 5 m) per year. Additionally, we find that the LOAs tend to approach from sunward and anti-sunward directions, with encounter velocities significantly lower than those of typical NEAs. These findings offer valuable insights in guiding targeted ground-based surveys and planetary defense efforts for LOAs in the future.