Dynamical Origin of (469219) Kamo`oalewa of Tianwen-2 Mission from the Main-Belt: $\nu_6$ Secular Resonance, Flora Family or 3:1 Resonance with Jupiter

TL;DR

This study uses long-term dynamical simulations to investigate the main-belt origins of near-Earth asteroid Kamo`oalewa, highlighting the most probable source regions and pathways to its current orbit.

Contribution

It identifies the $ u_6$ secular resonance as the most likely main-belt source of Kamo`oalewa through extensive simulation of asteroid transfer pathways.

Findings

Asteroids from $ u_6$, Flora, and 3:1J MMR can reach Kamo`oalewa-like orbits.

Transfer probability is highest from $ u_6$ (3.31%), then Flora (2.54%), and lowest from 3:1J MMR (0.39%).

Tianwen-2 will rendezvous with Kamo`oalewa in 2026 to analyze its composition and test origin hypotheses.

Abstract

China's Tianwen-2 mission, launched on 29 May 2025, targets the near-Earth object (469219) Kamo`oalewa, an Earth quasi-satellite trapped in a 1:1 mean-motion resonance with our planet. Determining the origin of Kamo`oalewa is central to understanding the formation pathways and dynamical evolution of Earth's quasi-satellite population. Here we show a strong possibility of main-belt origin for Kamo`oalewa using long-term dynamical simulations. We examine three candidate source regions: the $\nu_6$ secular resonance ($\nu_6$), the 3:1 mean-motion resonance with Jupiter (3:1J MMR), and the Flora family. A total of 42,825 test particles were integrated over 100 Myr. We find that asteroids from all three regions can be transported onto Kamo`oalewa-like orbits, albeit with markedly different efficiencies. Particles originating near the $\nu_6$ show the highest transfer probability (3.31%), followed by the Flora family (2.54%) and the 3:1J MMR (0.39%). We further identify representative dynamical pathways linking these source regions to Earth quasi-satellite orbits. The Tianwen-2 spacecraft is expected to rendezvous with Kamo`oalewa in 2026, performing close-proximity operations and returning samples. The mission will provide decisive observational constraints on the asteroid's composition and physical properties, offering a critical test of its proposed origin.