Recently, a research team from the Shanghai Astronomical Observatory (SHAO) of the Chinese Academy of Sciences (CAS), in collaboration with Anhui Normal University, used orbital similarity criteria and numerical simulations to systematically screen known near-Earth asteroids. They identified multiple groups of potential asteroid pairs that may share a common origin and estimated their possible separation times.

The findings were published in The Astrophysical Journal.

Near-Earth asteroids are asteroids with a perihelion distance of less than 1.3 astronomical units (AU). These objects can approach Earth and therefore pose a potential impact risk. An asteroid pair refers to two asteroids that exhibit high orbital similarity within the parameter space of their orbits but are not gravitationally bound to each other.

The orbits of near-Earth asteroids are influenced by both planetary gravitational forces and the Yarkovsky non-gravitational effect; their evolution is highly chaotic, making it difficult to maintain such orbital similarity over the long term, which results in an extremely rare number of confirmed asteroid pairs with shared origins—to date, only seven such pairs have been identified.

In this study, the research team systematically calculated the pairwise orbital similarity criterion (DSH) for known near-Earth asteroids, performed numerical simulations spanning 20,000 years on candidate pairs with high similarity scores, and analyzed their historical encounter frequencies, minimum distances, and relative velocities to infer potential fragmentation times.

The team identified three new candidate near-Earth asteroid pairs. The pair 2012 QG8 and 2024 GE1 experienced a close encounter approximately 1,000 years ago, with a distance of less than 10,000 km and a relative velocity below 1 m/s. The pair may have formed through the high-speed rotational breakup of a parent body driven by the YORP effect.

The pair 2022 MY3 and 2022 OP8 underwent a close approach approximately 100 years ago, with a distance of less than 2,000 km and a relative velocity below 1 m/s. Meanwhile, 2019 SK10 and 2012 SN30 experienced a close encounter approximately 16,000 years ago, making them a candidate for an even older asteroid pair.

The first author of this paper is LIU Ning, a master's student jointly trained by the SHAO and Anhui Normal University; the corresponding authors are SHI Jianchun from the SHAO and JIN Sheng from Anhui Normal University.

According to the researchers, the study deepens our understanding of the evolutionary mechanisms of near-Earth asteroids and the formation of small bodies in the Solar System. It also expands the sample of near-Earth asteroids, providing a basis for selecting potential targets for future deep-space exploration missions.