Asteroid 4 Vesta: dynamical and collisional evolution during the Late Heavy Bombardment

Abstract

Vesta is the only currently identified asteroid for which we possess samples, which revealed us that the asteroid is differentiated and possesses a relatively thin basaltic crust that survived to the evolution of the asteroid belt and the Solar System. However, little is know about the effects of past events like the Late Heavy Bombardment on this crust. We address this gap in our knowledge by simulating the LHB in the different dynamical scenarios proposed for the migration of the giant planets in the broad framework of the Nice Model. The results of simulations generate information about produced crater population, surface saturation, mass loss and mass gain of Vesta and number of energetic or catastrophic impacts during LHB. Our results reveal that planet-planet scattering is a dynamically favourable migration mechanism for the survival of Vesta and its crust. The number of impacts on Vesta estimated as due to the LHB is $31\pm 5$, i.e. about 5 times larger than the number of impacts that would have occurred in an unperturbed main belt in the same time interval. The contribution of a possible extended belt, instead, is quite limited and can be quantified in $2\pm 1$ impacts. The chance of energetic and catastrophic impacts is less than 10\% and is compatible with the absence of giant craters dated back to 4 Ga ago and with the survival of the asteroid during the LHB. The mass loss translates in the erosion of $3-5$ meters of the crust, consistently with the global survival of the basaltic crust of Vesta confirmed by the Dawn mission. Our analysis revealed that the contribution of the LHB to the cratering of Vesta' surface is not significant and is actually erased by the crater population produced by the following 4 Ga of collisional evolution of the asteroid, in agreement with the data provided by the Dawn mission.

12 pages, 4 figures, accepted for publication on the journal Icarus

References in corpus (6)

• Dynamics of the giant planets of the solar system in the gaseous proto-planetary disk and relationship to the current orbital architecture
• Constraining the cometary flux through the asteroid belt during the late heavy bombardment
• Constraining the Cratering Chronology of Vesta
• Jovian Early Bombardment: planetesimal erosion in the inner asteroid belt
• The contamination of the surface of Vesta by impacts and the delivery of the dark material
• The Formation of Jupiter, the Jovian Early Bombardment and the Delivery of Water to the Asteroid Belt: The Case of (4) Vesta

Cited by in corpus (4)

• The consequences of planetary migration on the minor bodies of the early Solar System
• Olivine on Vesta as exogenous contaminants brought by impacts: Constraints from modeling Vesta's collisional history and from impact simulations
• Scattering V-type asteroids during the giant planets instability: A step for Jupiter, a leap for basalt
• The late accretion and erosion of Vesta's crust recorded by eucrites and diogenites as an astrochemical window into the formation of Jupiter and the early evolution of the Solar System