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Physical parameters and orbital evolution of asteroids in retrograde orbits

I. Wlodarczyk (2024)

Published
Jul 1, 2024
Journal
Astronomy & Astrophysics · Vol. 687
DOI
10.1051/0004-6361/202348985

At a GlanceAI

Adds Yarkovsky/YORP to 10 Myr clone integrations of retrograde asteroids, quantifying chaos, spin evolution, and drift rates.

SummaryAI

This paper compiles orbital and physical parameters for all numbered retrograde asteroids (plus selected unnumbered ones) and follows their evolution with ensembles of orbital clones. By explicitly including Yarkovsky and YORP nongravitational forces, it shows these rare retrograde objects have strongly chaotic dynamics (short Lyapunov times) and that adding thermal forces typically shortens Lyapunov times relative to gravity-only models. Over 10 Myr, the simulations predict modest average spin-up (rotation periods decrease by ~8%) with a non-negligible minority spinning down, and a drift-rate (da/dt) distribution concentrated near zero but with an asymmetry toward positive drift. The results argue that long-term modeling of retrograde asteroids should not ignore nongravitational effects, even when they are hard to measure directly.

Method SnapshotAI

The study performs orbit determination (including fitted A2 where possible) and 10 Myr N-body forward integrations of 101-clone ensembles with Yarkovsky/YORP-enabled dynamics.

BackgroundAI

Familiarity with Solar System small-body dynamics (orbital elements, chaos/Lyapunov time) and thermal recoil effects (Yarkovsky/YORP).

It is studied the dynamical orbital and physical evolution of all 21 numbered and 13 selected unnumbered asteroids in retrograde orbits. They computed their starting orbital elements, absolute magnitudes, and diameters, together with the non-gravitational parameters A2 and da/dt.