Astronomy5 papers
Dynamics of unstable main belt asteroids
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Ivana Milić Žitnik
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Numerical analysis of Lyapunov times for trans-Neptunian objects and main-belt asteroids: stability, accuracy, and methodological comparisons
Paweł Wajer et al. (2026)
- Published
- Feb 12, 2026
- Journal
- Monthly Notices of the Royal Astronomical Society · Vol. 547 · No. 2
- DOI
- 10.1093/mnras/stag280
At a Glance
Clone-ensemble Lyapunov times are more robust than nominal-orbit values and reduce method bias for TNOs and outer MBAs.
Summary
This paper benchmarks three common numerical ways to compute Lyapunov times—variational equations and two renormalized “nearby trajectory” schemes—on both trans-Neptunian objects and outer main-belt asteroids. By repeating the calculation over 1001 orbital clones per object, it shows that ensemble statistics (especially medians) are often more reliable stability indicators than a single best-fit orbit, revealing multimodal or mixed stability that nominal-orbit estimates can miss (notably for 2010 HE79 and 2010 EL139). The study also finds method-to-method agreement is typically better for the (hot) TNO sample than for outer-belt asteroids, consistent with the main belt’s denser network of overlapping resonances, and it highlights cases where simplified dynamical models can strongly distort Lyapunov-time inference. Overall, it provides a practical framework for scaling Lyapunov-time stability classification to larger small-body populations while explicitly accounting for orbit uncertainty and numerical-method sensitivity.
Method Snapshot
High-accuracy N-body integrations (REBOUND/IAS15) compute finite-time Lyapunov indicators via variational equations and renormalized nearby-trajectory divergence, applied to large clone ensembles.
Background
Background in celestial mechanics/solar-system dynamics, chaos indicators (Lyapunov exponents), and numerical N-body integration methods.