Impact cratering on Mercury: consequences for the spin evolution

Abstract

Impact basins identified by Mariner 10 and Messenger flyby images provide us a fossilized record of the impactor flux of asteroids on Mercury during the last stages of the early Solar System. The distribution of these basins is not uniform across the surface, and is consistent with a primordial synchronous rotation (Wieczorek et al. 2012). By analyzing the size of the impacts, we show that the distribution for asteroid diameters D < 110 km is compatible with an index power law of 1.2, a value that matches the predicted primordial distribution of the main-belt. We then derive a simple collisional model coherent with the observations, and when combining it with the secular evolution of the spin of Mercury, we are able to reproduce the present 3/2 spin-orbit resonance (about 50% of chances), as well as a primordial synchronous rotation. This result is robust with respect to variations in the dissipation and collisional models, or in the initial spin state of the planet.

6 pages, 3 tables, 2 figures

References in corpus (5)

• Chaotic diffusion in the Solar System
• Secular evolution of a satellite by tidal effect. Application to Triton
• Mercury's capture into the 3/2 spin-orbit resonance including the effect of core-mantle friction
• A pre-Caloris synchronous rotation for Mercury
• Long-term evolution of the spin of Mercury I. Effect of the obliquity and core-mantle friction

Cited by in corpus (8)

• Spin-orbit evolution of Mercury revisited
• Spin-orbit coupling for tidally evolving super-Earths
• Complete Tidal Evolution of Pluto-Charon
• On the equilibrium figure of close-in planets and satellites
• Spin-orbital tidal dynamics and tidal heating in the TRAPPIST-1 multi-planet system
• Spin evolution of Earth-sized exoplanets, including atmospheric tides and core-mantle friction
• Tidal damping of the mutual inclination in hierachical systems
• Tidal evolution of the Pluto-Charon binary