The Yarkovsky effect on the long-term evolution of binary asteroids

Abstract

We explore the Yarkovsky effect on small binary asteroids. While significant attention has been given to the binary YORP effect, the Yarkovsky effect is often overlooked. We develop an analytical model for the binary Yarkovsky effect, considering both the Yarkovsky-Schach and planetary Yarkovsky components, and verify it against thermophysical numerical simulations. We find that the Yarkovsky force could change the mutual orbit when the asteroid's spin period is unequal to the orbital period. Our analysis predicts new evolutionary paths for binaries. For a prograde asynchronous secondary, the Yarkovsky force will migrate the satellite towards the location of the synchronous orbit on ~100 kyr timescales, which could be faster than other synchronization processes such as YORP and tides. For retrograde secondaries, the Yarkovsky force always migrates the secondary outwards, which could produce asteroid pairs with opposite spin poles. Satellites spinning faster than the Roche limit orbit period (e.g. from ~4h to ~10h) will migrate inwards until they disrupt, reshape, or form a contact binary. We also predict a short-lived equilibrium state for asynchronous secondaries where the Yarkovsky force is balanced by tides. We provide calculations of the Yarkovsky-induced drift rate for known asynchronous binaries. If the NASA DART impact broke Dimorphos from synchronous rotation, we predict that Dimorphos's orbit will shrink by \dot a ~ 7 cm/yr, which can be measured by the Hera mission. We also speculate that the Yarkovsky force may have synchronized the Dinkinesh-Selam system after a possible merger of Selam's two lobes.

14 pages, 3 figures. Accepted for publication in the Astrophysical Journal Letters

References in corpus (16)

• Successful Kinetic Impact into an Asteroid for Planetary Defense
• Tidal Evolution of Rubble Piles
• Asteroid pairs: a complex picture
• Tangential component of the YORP effect
• A 3-dimensional model of tangential YORP
• Coupled Spin and Shape Evolution of Small Rubble-Pile Asteroids: Self-Limitation of the YORP Effect
• The Excited Spin State of Dimorphos Resulting from the DART Impact
• A Contact Binary Satellite of the Asteroid (152830) Dinkinesh
• Direct $N$-body simulations of satellite formation around small asteroids: insights from DART's encounter with the Didymos system
• Binary YORP and Evolution of Binary Asteroids
• Dimorphos orbit determination from mutual events photometry
• Non-principal axis rotation in binary asteroid systems and how it weakens the BYORP effect
• The crater-induced YORP effect
• 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
• Tidal dissipation of binaries in asteroid pairs

Cited by in corpus (7)

• Spin states of X-complex asteroids in the inner main belt -- I. Investigating the Athor and Zita collisional families
• The binary Yarkovsky effect on the primary asteroid with applications to singly synchronous binary asteroids
• Time-Adaptive PIROCK Method with Error Control for Multi-Fluid and Single-Fluid MHD Systems
• Confined tumbling state as the origin of the excess of slowly rotating asteroids
• A 3D thermophysical model for binary asteroid systems: Application to the BYORP effect on (175706) 1996 FG3
• The dependence of the asteroid rotation on their composition
• Numerical Validation of the Yarkovsky Effect in Super-Fast Rotating Asteroids