Co-orbital asteroids of terrestrial planets affected by the von Zeipel─Lidov─Kozai mechanism
Carruba, V. et al. (2026)
- Published
- Feb 1, 2026
- DOI
- 10.1007/s10569-026-10275-5
At a GlanceAI
Venus/Earth/Mars co-orbitals show Lidov-Kozai protection; some Earth co-orbitals and Mars 2017 XG62 librate at Kozai equilibria, boosting stability.
SummaryAI
This paper connects the von Zeipel–Lidov–Kozai (Lidov-Kozai) mechanism to the long-term behavior of terrestrial-planet co-orbital asteroids (a subset of NEOs), showing that Kozai-type libration can act as a close-encounter-avoidance mechanism. In a low-e/i regime dominated by Earth–Venus perturbations, Kozai equilibria at argument of perihelion 0 and 180 deg can stabilize Earth co-orbitals for ~10^5 yr by maintaining encounter-safe geometry. In a higher-e/i regime, the classical Kozai equilibria at 90 and 270 deg appear, with Mars co-orbital 2017 XG62 identified as a rare high-inclination Kozai librator.
Method SnapshotAI
They combine semi-analytic von Zeipel–Lidov–Kozai secular models with SWIFT and REBOUND N-body integrations to classify Kozai libration states and stability.
Background
Requires familiarity with co-orbital resonance dynamics (Trojan/horseshoe/quasi-satellite), secular perturbations, and the von Zeipel–Lidov–Kozai mechanism.
AI Abstract
We investigate the dynamical behavior of co-orbital asteroids of Venus, Earth, and Mars potentially affected by the von Zeipel–Lidov–Kozai (ZLK) mechanism. Semi-analytical models of ZLK dynamics for near-Earth objects in the terrestrial-planet region predict that at high eccentricities and inclinations (with i_max > 30 deg), equilibrium points should appear at argument of perihelion 90 deg and 270 deg. At low eccentricities and inclinations near Earth and Venus, perturbations from these two planets dominate, producing two equilibrium points at 0 deg and 180 deg. Using numerical simulations with the SWIFT and REBOUND integrators, we classify the Kozai states of known co-orbitals and assess their long-term stability. We find that no current Venus co-orbital is a robust ZLK resonator, while several Earth co-orbitals and one Mars co-orbital (2017 XG62) exhibit libration around one of the four ZLK equilibrium points. Libration around the 0 deg and 180 deg equilibrium points protects asteroids from close encounters with Earth, enhancing long-term stability on timescales of about 10^5 years. 2017 XG62 is the only known terrestrial-planet co-orbital currently librating around the high-inclination 90 deg equilibrium point, preventing close encounters with other terrestrial planets.