A pre-flyby view on the origin of asteroid Donaldjohanson, a target of the NASA Lucy mission

Abstract: The NASA Lucy mission is scheduled to fly-by the main belt asteroid (52246) Donaldjohanson on April 20, 2025. Donaldjohanson (DJ hereafter) is a member of the primitive (C-type class) Erigone collisional asteroid family located in the inner main belt in proximity of the source regions of asteroid (101955)~Bennu and (162173)~Ryugu, visited respectively by OSIRIS-REx and Hayabusa2 missions. In this paper we provide an updated model for the Erigone family age, and discuss DJ evolution resulting from non-gravitational forces (namely Yarkovsky and YORP), as well as its collisional evolution. We conclude the best-fit family age to be $\sim 155$~Myr, and that, on such timescales, both Yarkovsky and YORP effects may have affected the orbit and spin properties of DJ. Furthermore, we discuss how the NASA Lucy mission could provide independent insights on such processes, namely by constraining DJ shape, surface geology and cratering history.