Astronomy8 papers
Binary asteroids
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Ivana Milić Žitnik
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BYORP and Dissipation in Binary Asteroids: Lessons from DART
Matija Ćuk et al. (2024)
- Published
- Jul 1, 2024
- Journal
- The Planetary Science Journal · Vol. 5 · No. 7
- DOI
- 10.3847/PSJ/ad5d5e
At a Glance
DART data motivate weaker, size-dependent BYORP and episodic “landslide” dissipation as key drivers of small-binary evolution.
Summary
Using DART’s detailed view of Didymos–Dimorphos, the paper argues that many small-binary secondaries may be relatively smooth “debris piles,” which would make the BYORP radiation torque systematically weaker and more size-dependent than assumed from lumpy asteroid shapes. A simple synthetic-shape experiment shows BYORP strength is controlled mainly by absolute surface relief (meter-scale roughness), implying larger secondaries should have smaller dimensionless BYORP coefficients and helping reconcile the wide range of observed orbital period drifts. The authors also interpret Dimorphos’s apparent post-impact reshaping (oblate to more prolate) as evidence that dissipation may occur in short, high-mobility episodes (e.g., impact-triggered landslides) rather than steady, long-term tidal damping. If correct, binary properties like low eccentricity and near-synchronous rotation may record recent dissipative events, and Hera can test whether Dimorphos continues to relax dynamically by 2026.
Method Snapshot
Combines idealized BYORP torque calculations on randomized rough ellipsoids with order-of-magnitude energy accounting for Dimorphos’s post-DART relaxation.
Background
Background in small-body dynamics (YORP/BYORP, tides) and rubble-pile asteroid geophysics/orbital mechanics.