Detectability of Lunar-origin Asteroids in the LSST Era

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‘alewa 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, we predict an average detection rate of about six LOAs (with D > 5 m) per year. Additionally, we find that the LOAs tend to approach from sunward and antisunward 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.