Program: GN-2024B-FT-106

Minimoons are a class of asteroids temporarily captured in orbit around the Earth in the Earth-Moon system. Out of ~1 million known asteroids, only three minimoons are known to exist: 1998 RH120, 2020 CD3, and 2024 PT5 (hereafter PT5). The numerical integration of the orbit of PT5 indicates that it has been captured in orbit around the Earth for the past month and will leave the Earth-Moon system in a few months. There are two competing hypotheses for the origin of minimoons: capture from the general near-Earth asteroid population and capture of debris originating from impacts on the Moon. Accurately tracing the orbit of PT5 backward for more than a hundred years is impossible due to dynamic chaos. Therefore, we propose an observational approach to constrain its origin. We will take a combination of visible and near-infrared spectrophotometry between 0.5-2.2 microns with GMOS-N/GNIRS to determine the spectra of PT5 between 0.5 and 2.2 microns constraining its composition and determining whether it consists of asteroidal or lunar material. Our results are likely to have a high impact in either case, with the asteroids having a lunar or asteroidal origin, as either case will drastically expand our knowledge of the population of ETs and the bombardment history of the moon.