The Dynamical Fate of Lunar Ejecta and the Possible Origin of Earth’s Quasi-satellite Kamo’oalewa

Among the population of Earth’s co-orbitals, the recently discovered quasi-satellite (QS) Kamo’oalewa outstands due to its long-term residence in its current QS state, and the recurrent transitions to horseshoe state revelead by numerical simulations. Kamo’oalewa’s unknown origin, curious dynamics and close proximity to Earth contribute for making it a suitable and compelling candidate for coming space missions (Venigalla et al. 2017; Jin et al. 2020).

Some hypotheses for Kamo’oalewa’s origin have been proposed based on the available information of its physical properties. In particular, Sharkey et al (2021) measured its reflectance spectrum and found it to have a L-type profile, which resembles lunar silicates, posing the possibility that Kamo’oalewa may be lunar ejecta from a metereoidal impact.

We test this hypothesis by numerically simulating test particles (using the open source REBOUND N-body software package) launched from the Moon’s surface and following their subsequent orbital evolution. These simulated ejecta are launched from multiple locations at the Lunar surface and with a variety of launching speeds above the lunar escape velocity. We find that the fate of a small fraction of these ejecta include reaching co-orbital states compatible with Kamo’oalewa’s dynamical behavior.

We will present these results as they relate to Kamo’oalewa’s origin and discuss how such simulations can enable exploration of the rich multi-time scale dynamics in the neighborhood of the Earth-Moon system.