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Barnouin OS, Daly MG, Palmer EE, Gaskell RW, Weirich JR, Johnson CL, Asad MMA, Roberts JH, Perry ME, Susorney HCM, Daly RT, Bierhaus EB, Seabrook JA, Espiritu RC, Nair AH, Nguyen L, Neumann GA, Ernst CM, Boynton WV, Nolan MC, Adam CD, Moreau MC, Risk B, D'Aubigny CD, Jawin ER, Walsh KJ, Michel P, Schwartz SR, Ballouz RL, Mazarico EM, Scheeres DJ, McMahon J, Bottke W, Sugita S, Hirata N, Hirata N, Watanabe S, Burke KN, DellaGuistina DN, Bennett CA, Lauretta DS. Shape of (101955) Bennu indicative of a rubble pile with internal stiffness. Nat Geosci 2019; 12:247-252. [PMID: 31080497 PMCID: PMC6505705 DOI: 10.1038/s41561-019-0330-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 02/15/2019] [Indexed: 05/18/2023]
Abstract
The shapes of asteroids reflect interplay between their interior properties and the processes responsible for their formation and evolution as they journey through the Solar System. Prior to the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) mission, Earth-based radar imaging gave an overview of (101955) Bennu's shape. Here, we construct a high-resolution shape model from OSIRIS-REx images. We find that Bennu's top-like shape, considerable macroporosity, and prominent surface boulders suggest that it is a rubble pile. High-standing, north-south ridges that extend from pole to pole, many long grooves, and surface mass wasting indicate some low levels of internal friction and/or cohesion. Our shape model indicates that, similar to other top-shaped asteroids, Bennu formed by reaccumulation and underwent past periods of fast spin leading to its current shape. Today, Bennu might follow a different evolutionary pathway, with interior stiffness permitting surface cracking and mass wasting.
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Affiliation(s)
- O S Barnouin
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - M G Daly
- The Centre for Research in Earth and Space Science, York University, Toronto, Ontario, Canada
| | - E E Palmer
- Planetary Science Institute, Tucson, AZ, USA
| | - R W Gaskell
- Planetary Science Institute, Tucson, AZ, USA
| | - J R Weirich
- Planetary Science Institute, Tucson, AZ, USA
| | - C L Johnson
- Planetary Science Institute, Tucson, AZ, USA
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - M M Al Asad
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - J H Roberts
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - M E Perry
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - H C M Susorney
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - R T Daly
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - E B Bierhaus
- Lockheed Martin Space Systems Company, Denver, CO, USA
| | | | - R C Espiritu
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - A H Nair
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - L Nguyen
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - G A Neumann
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - C M Ernst
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - W V Boynton
- Lunar Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - M C Nolan
- Lunar Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - C D Adam
- KinetX Aerospace, Inc. Simi Valley, CA, USA
| | - M C Moreau
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - B Risk
- Lunar Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | - E R Jawin
- Smithsonian Institution National Museum of Natural History, Washington, DC, USA
| | - K J Walsh
- Southwest Research Institute, Boulder, CO, USA
| | - P Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - S R Schwartz
- Lunar Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - R-L Ballouz
- Lunar Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - E M Mazarico
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - D J Scheeres
- Department of Aerospace Engineering Sciences, University of Colorado, Boulder, CO, USA
| | - J McMahon
- Department of Aerospace Engineering Sciences, University of Colorado, Boulder, CO, USA
| | - W Bottke
- Southwest Research Institute, Boulder, CO, USA
| | - S Sugita
- University of Tokyo, Tokyo, Japan
| | - N Hirata
- Aizu University, Aizu-Wakamatsu, Japan
| | | | - S Watanabe
- Nagoya University, Nagoya, Japan
- Institute of Space and Astronautical Science, JAXA, Sagamihara, Japan
| | - K N Burke
- Lunar Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | - C A Bennett
- Lunar Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - D S Lauretta
- Lunar Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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