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Zhang Y, Michel P, Barnouin OS, Roberts JH, Daly MG, Ballouz RL, Walsh KJ, Richardson DC, Hartzell CM, Lauretta DS. Inferring interiors and structural history of top-shaped asteroids from external properties of asteroid (101955) Bennu. Nat Commun 2022; 13:4589. [PMID: 35933392 PMCID: PMC9357032 DOI: 10.1038/s41467-022-32288-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 07/20/2022] [Indexed: 11/30/2022] Open
Abstract
Asteroid interiors play a key role in our understanding of asteroid formation and evolution. As no direct interior probing has been done yet, characterisation of asteroids’ interiors relies on interpretations of external properties. Here we show, by numerical simulations, that the top-shaped rubble-pile asteroid (101955) Bennu’s geophysical response to spinup is highly sensitive to its material strength. This allows us to infer Bennu’s interior properties and provide general implications for top-shaped rubble piles’ structural evolution. We find that low-cohesion (≲0.78 Pa at surface and ≲1.3 Pa inside) and low-friction (friction angle ≲ 35∘) structures with several high-cohesion internal zones can consistently account for all the known geophysical characteristics of Bennu and explain the absence of moons. Furthermore, we reveal the underlying mechanisms that lead to different failure behaviours and identify the reconfiguration pathways of top-shaped asteroids as functions of their structural properties that either facilitate or prevent the formation of moons. Asteroid interiors are key to understand their formation and evolution. Here, the authors show that numerically simulated low-cohesion and low-friction structures with several high-cohesion internal zones can explain asteroid Bennu’s geophysical characteristics and the absence of the moons.
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Affiliation(s)
- Yun Zhang
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France. .,Department of Aerospace Engineering, University of Maryland, College Park, MD, USA.
| | - Patrick Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - Olivier S Barnouin
- The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD, USA
| | - James H Roberts
- The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD, USA
| | - Michael G Daly
- The Centre for Research in Earth and Space Science, York University, Toronto, ON, Canada
| | - Ronald-L Ballouz
- The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD, USA.,Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | | | - Christine M Hartzell
- Department of Aerospace Engineering, University of Maryland, College Park, MD, USA
| | - Dante S Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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Lauretta DS, Adam CD, Allen AJ, Ballouz RL, Barnouin OS, Becker KJ, Becker T, Bennett CA, Bierhaus EB, Bos BJ, Burns RD, Campins H, Cho Y, Christensen PR, Church ECA, Clark BE, Connolly HC, Daly MG, DellaGiustina DN, Drouet d’Aubigny CY, Emery JP, Enos HL, Freund Kasper S, Garvin JB, Getzandanner K, Golish DR, Hamilton VE, Hergenrother CW, Kaplan HH, Keller LP, Lessac-Chenen EJ, Liounis AJ, Ma H, McCarthy LK, Miller BD, Moreau MC, Morota T, Nelson DS, Nolau JO, Olds R, Pajola M, Pelgrift JY, Polit AT, Ravine MA, Reuter DC, Rizk B, Rozitis B, Ryan AJ, Sahr EM, Sakatani N, Seabrook JA, Selznick SH, Skeen MA, Simon AA, Sugita S, Walsh KJ, Westermann MM, Wolner CWV, Yumoto K. Spacecraft sample collection and subsurface excavation of asteroid (101955) Bennu. Science 2022; 377:285-291. [DOI: 10.1126/science.abm1018] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Carbonaceous asteroids, such as (101955) Bennu, preserve material from the early Solar System, including volatile compounds and organic molecules. We report spacecraft imaging and spectral data collected during and after retrieval of a sample from Bennu’s surface. The sampling event mobilized rocks and dust into a debris plume, excavating a 9-m-long elliptical crater. This exposed material that is darker, spectrally redder, and more abundant in fine particulates than the original surface. The bulk density of the displaced subsurface material was 500–700 kg per cubic meter, about half that of the whole asteroid. Particulates that landed on instrument optics spectrally resemble aqueously altered carbonaceous meteorites. The spacecraft stored 250 ± 101 g of material, which will be delivered to Earth in 2023.
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Affiliation(s)
- D. S. Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | - A. J. Allen
- Physics Department, University of Central Florida, Orlando, FL, USA
| | - R.-L. Ballouz
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - O. S. Barnouin
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - K. J. Becker
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - T. Becker
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - C. A. Bennett
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | - B. J. Bos
- Goddard Space Flight Center, Greenbelt, MD, USA
| | - R. D. Burns
- Goddard Space Flight Center, Greenbelt, MD, USA
| | - H. Campins
- Physics Department, University of Central Florida, Orlando, FL, USA
| | - Y. Cho
- Department of Earth and Planetary Environmental Science, University of Tokyo, Tokyo, Japan
| | - P. R. Christensen
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | | | - B. E. Clark
- Department of Physics and Astronomy, Ithaca College, Ithaca, NY, USA
| | - H. C. Connolly
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
- Department of Geology, Rowan University, Glassboro, NJ, USA
| | - M. G. Daly
- Department of Earth and Space Science and Engineering, York University, Toronto, ON, Canada
| | | | | | - J. P. Emery
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, USA
| | - H. L. Enos
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | | | | | - D. R. Golish
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | | | | | | | | | | | - H. Ma
- Lockheed Martin Space, Littleton, CO, USA
| | | | | | | | - T. Morota
- Department of Earth and Planetary Environmental Science, University of Tokyo, Tokyo, Japan
| | | | - J. O. Nolau
- Physics Department, University of Central Florida, Orlando, FL, USA
| | - R. Olds
- Lockheed Martin Space, Littleton, CO, USA
| | - M. Pajola
- INAF (Italian National Institute for Astrophysics) – Astronomical Observatory of Padova, Padova, Italy
| | | | - A. T. Polit
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | | | - B. Rizk
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - B. Rozitis
- School of Physical Sciences, Open University, Milton Keynes, UK
| | - A. J. Ryan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | - N. Sakatani
- Department of Physics, Rikkyo University, Tokyo, Japan
| | - J. A. Seabrook
- Department of Earth and Space Science and Engineering, York University, Toronto, ON, Canada
| | - S. H. Selznick
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | - A. A. Simon
- Goddard Space Flight Center, Greenbelt, MD, USA
| | - S. Sugita
- Department of Earth and Planetary Environmental Science, University of Tokyo, Tokyo, Japan
| | - K. J. Walsh
- Southwest Research Institute, Boulder, CO, USA
| | - M. M. Westermann
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - C. W. V. Wolner
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - K. Yumoto
- Department of Earth and Planetary Environmental Science, University of Tokyo, Tokyo, Japan
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