A record from an active asteroid preserved in a carbonaceous chondrite

Abstract

Multiple particle ejection and redeposition events on the surface of asteroid 101955 Bennu were observed frequently by NASA’s OSIRIS-REx mission and advanced our understanding of active asteroids. This finding motivated us to search for relicts of such activity in a Bennu analog – the carbonaceous chondrite Aguas Zarcas (AZ). Here we discovered compact fragments that were strongly shocked, redistributed on the parent body, and deposited into an unshocked lithology. While breccias in meteorites are common, this type of lithology has been rarely observed. However, it is consistent with the observed particle redeposition process on Bennu. In addition, we observed a match in the size distribution of the compact fragments with that of the Bennu ejecta, indicating that the same process operated on the AZ parent body. Our findings suggest that such mixing may have been unnoticed in most meteorites and that asteroid activity may be common but overlooked.