How to become a mini-moon: some hints from 2022 NX1

Abstract

Low-velocity encounters between our planet and any near-Earth object (NEO) in an Earth-like orbit may induce its temporary capture as a mini-moon. Such mini-moon episodes could lead the NEO to complete one or more revolutions around Earth when gravitationally bound, a temporarily-captured orbiter, like in the cases of 2006 RH120 and 2020 CD3; sometimes not even one revolution is completed, a temporarily-captured flyby, like in the case of 1991 VG. Asteroid 2022 NX1 experienced a temporarilycaptured flyby in 1981, has had another one in 2022, and will become a temporarily-captured orbiter in 2051. This object occupies the edge of Earth’s co-orbital space and sometimes it approaches us following a horseshoe path.