Systematic structure and sinks in the YORP effect

Abstract

There is a correlation between the components of the YORP effect of most asteroids, which drives the obliquity and spin rate of the affected bodies in a consistent pattern. This allows for a clear and unambiguous picture for how the spin rates and poles of asteroids affected by YORP will evolve and simplifies the overall picture for how populations will migrate on average. The YORP effect can also lead to a previously unexplored equilibrium state for affected bodies. This equilibrium state is a function of the usual "normal YORP" effect (which arises due to the global shape asymmetry of the asteroid) and the "tangential YORP" (which arises due the transport of thermal energy through rocky surface features). Estimates from current shape models show that 10-20\% of asteroids have the proper condition to be captured in this equilibrium state, indicating that the occurrence of this state may be significant. The existence of this attractor for the asteroid population means that objects affected by YORP may leave their usual YORP cycles and maintain a constant spin rate over long time periods -- this has significant implications for our interpretation of asteroid spin rate evolution and related theories for their physical evolution.

15 pages, 11 figures. Accepted to The Astronomical Journal

References in corpus (11)

• The Yarkovsky and YORP Effects
• Extreme Sensitivity of the YORP Effect to Small-Scale Topography
• A 3-dimensional model of tangential YORP
• Tangential component of the YORP effect
• The thermal emission from boulders on (25143) Itokawa and general implications for the YORP effect
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• Analytic model for tangential YORP
• YORP torques with 1D thermal model
• Obliquity dependence of the tangential YORP
• Equilibrium rotation states of doubly synchronous binary asteroids
• A new equilibrium state for singly synchronous binary asteroids

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• Evolution of an asteroid family under YORP, Yarkovsky and collisions
• A semi-analytical thermal model for craters with application to the crater-induced YORP effect
• Limiting behavior of asteroid obliquity and spin using a semi-analytic thermal model of the YORP effect
• Interstellar Asteroid Rotation with the Mechanical Torque Produced by Interstellar Medium
• Shape model and rotation acceleration of (1685) Toro and (85989) 1999 JD6 from optical observations
• Confined tumbling state as the origin of the excess of slowly rotating asteroids
• Exploring rotational properties and the YORP effect in asteroid families
• Asteroid pairs: method validation and new candidates