The Formation of the Wide Asynchronous Binary Asteroid Population

Abstract

We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semi-major axes relative to most near-Earth and Main Belt asteroid systems. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, planetary flybys and directly from rotational fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (i) these systems are formed from rotational fission, (ii) their satellites are tidally locked, (iii) their orbits are expanded by the BYORP effect, (iv) their satellites de-synchronize due to the adiabatic invariance between the libration of the secondary and the mutual orbit, and (v) the secondary avoids resynchronization due to the the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torque that acts on the system. After detailing the theory, we analyze each of the wide asynchronous binary members and candidates to assess their most likely formation mechanism. Finally, we suggest possible future observations to check and constrain our hypothesis.

Accepted ApJ

References in corpus (9)

• Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems
• Formation of asteroid pairs by rotational fission
• Tidal Evolution of Rubble Piles
• Multiple Asteroid Systems: Dimensions and Thermal Properties from Spitzer Space Telescope and Ground-Based Observations
• Main Belt Binary Asteroidal Systems With Eccentric Mutual Orbits
• Tangential component of the YORP effect
• A 3-dimensional model of tangential YORP
• Asteroid rotation excitation by subcatastrophic impacts
• Rotation Periods of Binary Asteroids with Large Separations - Confronting the Escaping Ejecta Binaries Model with Observations

Cited by in corpus (21)

• The Yarkovsky and YORP Effects
• Asteroid Systems: Binaries, Triples, and Pairs
• Ejecta Cloud from a Kinetic Impact on the Secondary of a Binary Asteroid: I. Mechanical Environment and Dynamic Model
• Near-Earth Asteroid Satellite Spins Under Spin-Orbit Coupling
• Composition, Mineralogy, and Porosity of Multiple Asteroid Systems from Visible and Near-infrared Spectral Data
• A binary main belt comet
• Disaggregation of Small, Cohesive Rubble Pile Asteroids due to YORP
• The Dynamical State of the Didymos System Before and After the DART Impact
• Matching asteroid population characteristics with a model constructed from the YORP-induced rotational fission hypothesis
• Energy Dissipation in Synchronous Binary Asteroids
• Rotationally Resolved Spectroscopy of Asteroid Pairs: No Spectral Variation Suggests Fission is followed by Settling of Dust
• The Yarkovsky effect on the long-term evolution of binary asteroids
• Deficit of primitive compositions in binary asteroids and pairs
• Breakup of the Synchronous State of Binary Asteroid Systems
• A semi-analytical thermal model for craters with application to the crater-induced YORP effect
• Component properties and mutual orbit of binary main-belt comet 288P/(300163) 2006 VW139
• Improved Algorithms for Radar-based Reconstruction of Asteroid Shapes
• The binary Yarkovsky effect on the primary asteroid with applications to singly synchronous binary asteroids
• Small asteroid system evolution
• Multiple origins of asteroid pairs
• Orbits of very distant asteroid satellites