The Link between Athor and EL Meteorites Does Not Constrain the Timing of the Giant Planet Instability

Abstract The asteroid Athor, residing today in the inner main asteroid belt, has been recently identified as the source of EL enstatite meteorites to Earth. It has been argued that Athor formed in the terrestrial region—as indicated by a similarity in isotopic compositions between Earth and EL meteorites—and was implanted in the belt ≳60 Myr after the formation of the solar system. A recently published study modeling Athor’s implantation in the belt further concluded, using an idealized set of numerical simulations, that Athor could not have been scattered from the terrestrial region and implanted at its current location unless the giant planet dynamical instability occurred after Athor’s implantation (≳60 Myr). In this work, we revisit this problem with a comprehensive suite of dynamical simulations of the implantation of asteroids into the belt during the terrestrial planet accretion. We find that Athor-like objects can in fact be implanted into the belt long after the giant planets’ dynamical instability. The probability of implanting Athor analogs when the instability occurs at ≲15 Myr is at most a factor of ∼2 lower than that of an instability occurring ∼100 Myr after the solar system formation. Moreover, Athor’s implantation can occur up to ≳100 Myr after the giant planet instability. We conclude that Athor’s link to EL meteorites does not constrain the timing of the solar system’s dynamical instability.