@article{cea4ce6657fe4a1eb418a61934245f2f,
title = "Exogenic basalt on asteroid (101955) Bennu",
abstract = "When rubble-pile asteroid 2008 TC3 impacted Earth on 7 October 2008, the recovered rock fragments indicated that such asteroids can contain exogenic material1,2. However, spacecraft missions to date have only observed exogenous contamination on large, monolithic asteroids that are impervious to collisional disruption3,4. Here, we report the presence of metre-scale exogenic boulders on the surface of near-Earth asteroid (101955) Bennu—the 0.5-km-diameter, rubble-pile target of the OSIRIS-REx mission5 that has been spectroscopically linked to the CM carbonaceous chondrite meteorites6. Hyperspectral data indicate that the exogenic boulders have the same distinctive pyroxene composition as the howardite–eucrite–diogenite (HED) meteorites that come from (4) Vesta, a 525-km-diameter asteroid that has undergone differentiation and extensive igneous processing7–9. Delivery scenarios include the infall of Vesta fragments directly onto Bennu or indirectly onto Bennu{\textquoteright}s parent body, where the latter{\textquoteright}s disruption created Bennu from a mixture of endogenous and exogenic debris. Our findings demonstrate that rubble-pile asteroids can preserve evidence of inter-asteroid mixing that took place at macroscopic scales well after planetesimal formation ended. Accordingly, the presence of HED-like material on the surface of Bennu provides previously unrecognized constraints on the collisional and dynamical evolution of the inner main belt.",
author = "DellaGiustina, {D. N.} and Kaplan, {H. H.} and Simon, {A. A.} and Bottke, {W. F.} and C. Avdellidou and M. Delbo and Ballouz, {R. L.} and Golish, {D. R.} and Walsh, {K. J.} and M. Popescu and H. Campins and Barucci, {M. A.} and G. Poggiali and Daly, {R. T.} and {Le Corre}, L. and Hamilton, {V. E.} and N. Porter and Jawin, {E. R.} and McCoy, {T. J.} and Connolly, {H. C.} and Garcia, {J. L.Rizos} and E. Tatsumi and {de Leon}, J. and J. Licandro and S. Fornasier and Daly, {M. G.} and {Al Asad}, {M. M.} and L. Philpott and J. Seabrook and Barnouin, {O. S.} and Clark, {B. E.} and Nolan, {M. C.} and Howell, {E. S.} and Binzel, {R. P.} and B. Rizk and Reuter, {D. C.} and Lauretta, {D. S.}",
note = "Funding Information: This material is based upon work supported by NASA under contract NNM10AA11C issued through the New Frontiers Program. The work of C.A. was supported by the French National Research Agency under the project {\textquoteleft}Investissements d{\textquoteright}Avenir{\textquoteright} UCAJEDI ANR-15-IDEX-01. C.A. and M.D. would like to acknowledge the French space agency CNES and support from the ANR {\textquoteleft}ORIGINS{\textquoteright} (ANR-18-CE31-0014). M.A.B. also acknowledges support from CNES the French space agency. G.P. acknowledges support from the INAF-Astrophysical Observatory of Arcetri, which is supported by Italian Space Agency agreement no. 2017-37-H.0. E.T. was supported by the JSPS core-to-core program International Planetary Network. The OLA instrument and funding for M.G.D., M.M.A.A., L.P. and J.S. is provided by the Canadian Space Agency. This research uses spectra acquired at the NASA RELAB facility at Brown University. This work also makes use of data provided by the Minor Planet Physical Properties Catalogue (MP3C) of the Observatoire de la C{\^o}te d{\textquoteright}Azur. We thank the entire OSIRIS-REx team for making the encounter with Bennu possible. Publisher Copyright: {\textcopyright} 2020, The Author(s), under exclusive licence to Springer Nature Limited.",
year = "2021",
month = jan,
doi = "10.1038/s41550-020-1195-z",
language = "English (US)",
volume = "5",
pages = "31--38",
journal = "Nature Astronomy",
issn = "2397-3366",
publisher = "Nature Publishing Group",
number = "1",
}