Provenance of the bright boulders on (101955) Bennu

In-situ observations of the asteroid (101 955) Bennu during NASA’s OSIRIS-REx mission revealed several bright boulders on its surface, which have been interpreted as exogenic, Vesta-like differentiated material from the inner Solar system. If accepted, this interpretation implies that Bennu acquired such material after its late emplacement into the inner Solar system. Here, we suggest and demonstrate that basaltic material with isotopic affinities similar to those of the carbonaceous chondrites provides an equally plausible alternative. These findings provide perspective with regard to potential surface modification processes of asteroids and highlight an alternative interpretation of basaltic-like surfaces throughout the Solar system. These results further underscore the complex mixing and transport history of early-formed primitive bodies during the early Solar system.