1
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Cambioni S, Delbo M, Poggiali G, Avdellidou C, Ryan AJ, Deshapriya JDP, Asphaug E, Ballouz RL, Barucci MA, Bennett CA, Bottke WF, Brucato JR, Burke KN, Cloutis E, DellaGiustina DN, Emery JP, Rozitis B, Walsh KJ, Lauretta DS. Fine-regolith production on asteroids controlled by rock porosity. Nature 2021; 598:49-52. [PMID: 34616055 DOI: 10.1038/s41586-021-03816-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 07/08/2021] [Indexed: 11/09/2022]
Abstract
Spacecraft missions have observed regolith blankets of unconsolidated subcentimetre particles on stony asteroids1-3. Telescopic data have suggested the presence of regolith blankets also on carbonaceous asteroids, including (101955) Bennu4 and (162173) Ryugu5. However, despite observations of processes that are capable of comminuting boulders into unconsolidated materials, such as meteoroid bombardment6,7 and thermal cracking8, Bennu and Ryugu lack extensive areas covered in subcentimetre particles7,9. Here we report an inverse correlation between the local abundance of subcentimetre particles and the porosity of rocks on Bennu. We interpret this finding to mean that accumulation of unconsolidated subcentimetre particles is frustrated where the rocks are highly porous, which appears to be most of the surface10. The highly porous rocks are compressed rather than fragmented by meteoroid impacts, consistent with laboratory experiments11,12, and thermal cracking proceeds more slowly than in denser rocks. We infer that regolith blankets are uncommon on carbonaceous asteroids, which are the most numerous type of asteroid13. By contrast, these terrains should be common on stony asteroids, which have less porous rocks and are the second-most populous group by composition13. The higher porosity of carbonaceous asteroid materials may have aided in their compaction and cementation to form breccias, which dominate the carbonaceous chondrite meteorites14.
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Affiliation(s)
- S Cambioni
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA. .,Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.
| | - M Delbo
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - G Poggiali
- INAF - Osservatorio Astrofisico di Arcetri, Florence, Italy
| | - C Avdellidou
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - A J Ryan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - J D P Deshapriya
- LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Univ. Paris Diderot, Sorbonne Paris Cité, Meudon, France
| | - E Asphaug
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - R-L Ballouz
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - M A Barucci
- LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Univ. Paris Diderot, Sorbonne Paris Cité, Meudon, France
| | - C A Bennett
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - W F Bottke
- Southwest Research Institute, Boulder, CO, USA
| | - J R Brucato
- INAF - Osservatorio Astrofisico di Arcetri, Florence, Italy
| | - K N Burke
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - E Cloutis
- Department of Geography, University of Winnipeg, Winnipeg, Manitoba, Canada
| | - D N DellaGiustina
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - J P Emery
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, USA
| | - B Rozitis
- School of Physical Sciences, The Open University, Milton Keynes, UK
| | - K J Walsh
- Southwest Research Institute, Boulder, CO, USA
| | - D S Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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2
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DellaGiustina DN, Burke KN, Walsh KJ, Smith PH, Golish DR, Bierhaus EB, Ballouz RL, Becker TL, Campins H, Tatsumi E, Yumoto K, Sugita S, Deshapriya JDP, Cloutis EA, Clark BE, Hendrix AR, Sen A, Al Asad MM, Daly MG, Applin DM, Avdellidou C, Barucci MA, Becker KJ, Bennett CA, Bottke WF, Brodbeck JI, Connolly HC, Delbo M, de Leon J, Drouet d'Aubigny CY, Edmundson KL, Fornasier S, Hamilton VE, Hasselmann PH, Hergenrother CW, Howell ES, Jawin ER, Kaplan HH, Le Corre L, Lim LF, Li JY, Michel P, Molaro JL, Nolan MC, Nolau J, Pajola M, Parkinson A, Popescu M, Porter NA, Rizk B, Rizos JL, Ryan AJ, Rozitis B, Shultz NK, Simon AA, Trang D, Van Auken RB, Wolner CWV, Lauretta DS. Variations in color and reflectance on the surface of asteroid (101955) Bennu. Science 2020; 370:science.abc3660. [PMID: 33033157 DOI: 10.1126/science.abc3660] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 09/24/2020] [Indexed: 11/02/2022]
Abstract
Visible-wavelength color and reflectance provide information about the geologic history of planetary surfaces. Here we present multispectral images (0.44 to 0.89 micrometers) of near-Earth asteroid (101955) Bennu. The surface has variable colors overlain on a moderately blue global terrain. Two primary boulder types are distinguishable by their reflectance and texture. Space weathering of Bennu surface materials does not simply progress from red to blue (or vice versa). Instead, freshly exposed, redder surfaces initially brighten in the near-ultraviolet region (i.e., become bluer at shorter wavelengths), then brighten in the visible to near-infrared region, leading to Bennu's moderately blue average color. Craters indicate that the time scale of these color changes is ~105 years. We attribute the reflectance and color variation to a combination of primordial heterogeneity and varying exposure ages.
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Affiliation(s)
- D N DellaGiustina
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA. .,Department of Geosciences, University of Arizona, Tucson, AZ, USA
| | - K N Burke
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - K J Walsh
- Southwest Research Institute, Boulder, CO, USA
| | - P H Smith
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - D R Golish
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | - R-L Ballouz
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - T L Becker
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - H Campins
- Department of Physics, University of Central Florida, Orlando, FL, USA
| | - E Tatsumi
- Instituto de Astrofísica de Canarias and Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain.,Department of Earth and Planetary Science, University of Tokyo, Tokyo, 113-0033, Japan
| | - K Yumoto
- Department of Earth and Planetary Science, University of Tokyo, Tokyo, 113-0033, Japan
| | - S Sugita
- Department of Earth and Planetary Science, University of Tokyo, Tokyo, 113-0033, Japan
| | - J D Prasanna Deshapriya
- LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique), Observatoire de Paris, Université PSL (Paris Sciences & Lettres), CNRS (Centre National de la Recherche Scientifique), Université de Paris, Sorbonne Université, 92195 Meudon, France
| | - E A Cloutis
- Department of Geography, University of Winnipeg, Winnipeg, MB R3B 2E9, Canada
| | - B E Clark
- Department of Physics and Astronomy, Ithaca College, Ithaca, NY, USA
| | - A R Hendrix
- Planetary Science Institute, Tucson, AZ, USA
| | - A Sen
- Department of Physics and Astronomy, Ithaca College, Ithaca, NY, USA
| | - M M Al Asad
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada
| | - M G Daly
- The Centre for Research in Earth and Space Science, York University, Toronto, ON, Canada
| | - D M Applin
- Department of Geography, University of Winnipeg, Winnipeg, MB R3B 2E9, Canada
| | - C Avdellidou
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - M A Barucci
- LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique), Observatoire de Paris, Université PSL (Paris Sciences & Lettres), CNRS (Centre National de la Recherche Scientifique), Université de Paris, Sorbonne Université, 92195 Meudon, France
| | - K J Becker
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - C A Bennett
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - W F Bottke
- Southwest Research Institute, Boulder, CO, USA
| | - J I Brodbeck
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - H C Connolly
- Department of Geology, Rowan University, Glassboro, NJ, USA
| | - M Delbo
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - J de Leon
- Instituto de Astrofísica de Canarias and Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain
| | | | - K L Edmundson
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - S Fornasier
- LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique), Observatoire de Paris, Université PSL (Paris Sciences & Lettres), CNRS (Centre National de la Recherche Scientifique), Université de Paris, Sorbonne Université, 92195 Meudon, France.,Institut Universitaire de France (IUF), 1 rue Descartes, 75231 Paris CEDEX 05, France
| | | | - P H Hasselmann
- LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique), Observatoire de Paris, Université PSL (Paris Sciences & Lettres), CNRS (Centre National de la Recherche Scientifique), Université de Paris, Sorbonne Université, 92195 Meudon, France
| | - C W Hergenrother
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - E S Howell
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - E R Jawin
- Smithsonian Institution National Museum of Natural History, Washington, DC, USA
| | - H H Kaplan
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - L Le Corre
- Planetary Science Institute, Tucson, AZ, USA
| | - L F Lim
- Smithsonian Institution National Museum of Natural History, Washington, DC, USA
| | - J Y Li
- Planetary Science Institute, Tucson, AZ, USA
| | - P Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - J L Molaro
- Planetary Science Institute, Tucson, AZ, USA
| | - M C Nolan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - J Nolau
- Lockheed Martin Space, Littleton, CO, USA
| | - M Pajola
- Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Padova, Padua, Italy
| | - A Parkinson
- Department of Geography, University of Winnipeg, Winnipeg, MB R3B 2E9, Canada
| | - M Popescu
- Astronomical Institute of the Romanian Academy, Bucharest, Romania.,Instituto de Astrofísica de Canarias and Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain
| | - N A Porter
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - B Rizk
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - J L Rizos
- Instituto de Astrofísica de Canarias and Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain
| | - A J Ryan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - B Rozitis
- The School of Physical Sciences, The Open University, Milton Keynes, UK
| | - N K Shultz
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - A A Simon
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - D Trang
- University of Hawai'i at Mānoa, Hawai'i Institute of Geophysics and Planetology, Honolulu, HI, USA
| | - R B Van Auken
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - C W V Wolner
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - D S Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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3
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Rozitis B, Ryan AJ, Emery JP, Christensen PR, Hamilton VE, Simon AA, Reuter DC, Al Asad M, Ballouz RL, Bandfield JL, Barnouin OS, Bennett CA, Bernacki M, Burke KN, Cambioni S, Clark BE, Daly MG, Delbo M, DellaGiustina DN, Elder CM, Hanna RD, Haberle CW, Howell ES, Golish DR, Jawin ER, Kaplan HH, Lim LF, Molaro JL, Munoz DP, Nolan MC, Rizk B, Siegler MA, Susorney HCM, Walsh KJ, Lauretta DS. Asteroid (101955) Bennu's weak boulders and thermally anomalous equator. Sci Adv 2020; 6:eabc3699. [PMID: 33033037 PMCID: PMC7544501 DOI: 10.1126/sciadv.abc3699] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 09/09/2020] [Indexed: 05/18/2023]
Abstract
Thermal inertia and surface roughness are proxies for the physical characteristics of planetary surfaces. Global maps of these two properties distinguish the boulder population on near-Earth asteroid (NEA) (101955) Bennu into two types that differ in strength, and both have lower thermal inertia than expected for boulders and meteorites. Neither has strongly temperature-dependent thermal properties. The weaker boulder type probably would not survive atmospheric entry and thus may not be represented in the meteorite collection. The maps also show a high-thermal inertia band at Bennu's equator, which might be explained by processes such as compaction or strength sorting during mass movement, but these explanations are not wholly consistent with other data. Our findings imply that other C-complex NEAs likely have boulders similar to those on Bennu rather than finer-particulate regoliths. A tentative correlation between albedo and thermal inertia of C-complex NEAs may be due to relative abundances of boulder types.
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Affiliation(s)
- B Rozitis
- School of Physical Sciences, The Open University, Milton Keynes, UK.
| | - A J Ryan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - J P Emery
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, USA
| | - P R Christensen
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | | | - A A Simon
- NASA Goddard Space Flight Center, Solar System Exploration Division, Greenbelt, MD, USA
| | - D C Reuter
- NASA Goddard Space Flight Center, Solar System Exploration Division, Greenbelt, MD, USA
| | - M Al Asad
- Department of Earth, Atmospheric, and Ocean Science, University of British Columbia, Vancouver, BC, Canada
| | - 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
| | - C A Bennett
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - M Bernacki
- Mines ParisTech, PSL Research University, CEMEF-Centre de mise en forme des matériaux, Sophia Antipolis Cedex, France
| | - K N Burke
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - S Cambioni
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - B E Clark
- Department of Physics and Astronomy, Ithaca College, Ithaca, NY, USA
| | - M G Daly
- The Centre for Research in Earth and Space Science, York University, Toronto, ON, Canada
| | - M Delbo
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - D N DellaGiustina
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - C M Elder
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - R D Hanna
- Jackson School of Geosciences, University of Texas, Austin, TX, USA
| | - C W Haberle
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | - E S Howell
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - D R Golish
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - E R Jawin
- Smithsonian Institution National Museum of Natural History, Washington, DC, USA
| | - H H Kaplan
- NASA Goddard Space Flight Center, Solar System Exploration Division, Greenbelt, MD, USA
| | - L F Lim
- NASA Goddard Space Flight Center, Solar System Exploration Division, Greenbelt, MD, USA
| | - J L Molaro
- Planetary Science Institute, Tucson, AZ, USA
| | - D Pino Munoz
- Mines ParisTech, PSL Research University, CEMEF-Centre de mise en forme des matériaux, Sophia Antipolis Cedex, France
| | - M C Nolan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - B Rizk
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - M A Siegler
- Planetary Science Institute, Tucson, AZ, USA
| | - H C M Susorney
- School of Earth Sciences, University of Bristol, Bristol, UK
| | - K J Walsh
- Southwest Research Institute, Boulder, CO, USA
| | - D S Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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4
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Scheeres DJ, French AS, Tricarico P, Chesley SR, Takahashi Y, Farnocchia D, McMahon JW, Brack DN, Davis AB, Ballouz RL, Jawin ER, Rozitis B, Emery JP, Ryan AJ, Park RS, Rush BP, Mastrodemos N, Kennedy BM, Bellerose J, Lubey DP, Velez D, Vaughan AT, Leonard JM, Geeraert J, Page B, Antreasian P, Mazarico E, Getzandanner K, Rowlands D, Moreau MC, Small J, Highsmith DE, Goossens S, Palmer EE, Weirich JR, Gaskell RW, Barnouin OS, Daly MG, Seabrook JA, Al Asad MM, Philpott LC, Johnson CL, Hartzell CM, Hamilton VE, Michel P, Walsh KJ, Nolan MC, Lauretta DS. Heterogeneous mass distribution of the rubble-pile asteroid (101955) Bennu. Sci Adv 2020; 6:eabc3350. [PMID: 33033036 PMCID: PMC7544499 DOI: 10.1126/sciadv.abc3350] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 09/16/2020] [Indexed: 05/18/2023]
Abstract
The gravity field of a small body provides insight into its internal mass distribution. We used two approaches to measure the gravity field of the rubble-pile asteroid (101955) Bennu: (i) tracking and modeling the spacecraft in orbit about the asteroid and (ii) tracking and modeling pebble-sized particles naturally ejected from Bennu's surface into sustained orbits. These approaches yield statistically consistent results up to degree and order 3, with the particle-based field being statistically significant up to degree and order 9. Comparisons with a constant-density shape model show that Bennu has a heterogeneous mass distribution. These deviations can be modeled with lower densities at Bennu's equatorial bulge and center. The lower-density equator is consistent with recent migration and redistribution of material. The lower-density center is consistent with a past period of rapid rotation, either from a previous Yarkovsky-O'Keefe-Radzievskii-Paddack cycle or arising during Bennu's accretion following the disruption of its parent body.
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Affiliation(s)
- D J Scheeres
- Smead Department of Aerospace Engineering Sciences, University of Colorado, Boulder, CO, USA.
| | - A S French
- Smead Department of Aerospace Engineering Sciences, University of Colorado, Boulder, CO, USA
| | - P Tricarico
- Planetary Science Institute, Tucson, AZ, USA
| | - S R Chesley
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Y Takahashi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - D Farnocchia
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - J W McMahon
- Smead Department of Aerospace Engineering Sciences, University of Colorado, Boulder, CO, USA
| | - D N Brack
- Smead Department of Aerospace Engineering Sciences, University of Colorado, Boulder, CO, USA
| | - A B Davis
- Smead Department of Aerospace Engineering Sciences, University of Colorado, Boulder, CO, USA
| | - R-L Ballouz
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - E R Jawin
- Smithsonian Institution National Museum of Natural History, Washington, DC, USA
| | - B Rozitis
- Planetary and Space Sciences, School of Physical Sciences, The Open University, Milton Keynes, UK
| | - J P Emery
- Department of Astronomy and Planetary Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - A J Ryan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - R S Park
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - B P Rush
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - N Mastrodemos
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - B M Kennedy
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - J Bellerose
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - D P Lubey
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - D Velez
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - A T Vaughan
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | - J Geeraert
- KinetX Aerospace Inc., Simi Valley, CA, USA
| | - B Page
- KinetX Aerospace Inc., Simi Valley, CA, USA
| | | | - E Mazarico
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | | | - D Rowlands
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - M C Moreau
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - J Small
- Aerospace Corporation, Chantilly, VA, USA
| | | | - S Goossens
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
- Center for Research and Exploration in Space Science and Technology, University of Maryland, Baltimore County, Baltimore, MD, USA
| | - E E Palmer
- Planetary Science Institute, Tucson, AZ, USA
| | - J R Weirich
- Planetary Science Institute, Tucson, AZ, USA
| | - R W Gaskell
- Planetary Science Institute, Tucson, AZ, USA
| | - 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, ON, Canada
| | - J A Seabrook
- The Centre for Research in Earth and Space Science, York University, Toronto, ON, Canada
| | - M M Al Asad
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - L C Philpott
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - C L Johnson
- Planetary Science Institute, Tucson, AZ, USA
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - C M Hartzell
- Department of Aerospace Engineering, University of Maryland, College Park, MD, USA
| | - V E Hamilton
- Department of Space Studies, Southwest Research Institute, Boulder, CO, USA
| | - P Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - K J Walsh
- Department of Space Studies, Southwest Research Institute, Boulder, CO, USA
| | - M C Nolan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - D S Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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5
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Daly MG, Barnouin OS, Seabrook JA, Roberts J, Dickinson C, Walsh KJ, Jawin ER, Palmer EE, Gaskell R, Weirich J, Haltigin T, Gaudreau D, Brunet C, Cunningham G, Michel P, Zhang Y, Ballouz RL, Neumann G, Perry ME, Philpott L, Al Asad MM, Johnson CL, Adam CD, Leonard JM, Geeraert JL, Getzandanner K, Nolan MC, Daly RT, Bierhaus EB, Mazarico E, Rozitis B, Ryan AJ, DellaGiustina DN, Rizk B, Susorney HCM, Enos HL, Lauretta DS. Hemispherical differences in the shape and topography of asteroid (101955) Bennu. Sci Adv 2020; 6:eabd3649. [PMID: 33033038 PMCID: PMC7544500 DOI: 10.1126/sciadv.abd3649] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/14/2020] [Indexed: 05/18/2023]
Abstract
We investigate the shape of near-Earth asteroid (101955) Bennu by constructing a high-resolution (20 cm) global digital terrain model from laser altimeter data. By modeling the northern and southern hemispheres separately, we find that longitudinal ridges previously identified in the north extend into the south but are obscured there by surface material. In the south, more numerous large boulders effectively retain surface materials and imply a higher average strength at depth to support them. The north has fewer large boulders and more evidence of boulder dynamics (toppling and downslope movement) and surface flow. These factors result in Bennu's southern hemisphere being rounder and smoother, whereas its northern hemisphere has higher slopes and a less regular shape. We infer an originally asymmetric distribution of large boulders followed by a partial disruption, leading to wedge formation in Bennu's history.
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Affiliation(s)
- M G Daly
- The Centre for Research in Earth and Space Science, York University, Toronto, ON, Canada.
| | - O S Barnouin
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - J A Seabrook
- The Centre for Research in Earth and Space Science, York University, Toronto, ON, Canada
| | - J Roberts
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | | | - K J Walsh
- Southwest Research Institute, Boulder, CO, USA
| | - E R Jawin
- Smithsonian Institution National Museum of Natural History, Washington, DC, USA
| | - E E Palmer
- Planetary Science Institute, Tucson, AZ, USA
| | - R Gaskell
- Planetary Science Institute, Tucson, AZ, USA
| | - J Weirich
- Planetary Science Institute, Tucson, AZ, USA
| | - T Haltigin
- Canadian Space Agency, St. Hubert, QC, Canada
| | - D Gaudreau
- Canadian Space Agency, St. Hubert, QC, Canada
| | - C Brunet
- Canadian Space Agency, St. Hubert, QC, Canada
| | | | - P Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - Y Zhang
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - R-L Ballouz
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - G Neumann
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - M E Perry
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - L Philpott
- University of British Columbia, Vancouver, BC, Canada
| | - M M Al Asad
- University of British Columbia, Vancouver, BC, Canada
| | - C L Johnson
- University of British Columbia, Vancouver, BC, Canada
- Planetary Science Institute, Tucson, AZ, USA
| | - C D Adam
- KinetX Inc., Simi Valley, CA, USA
| | | | | | | | | | - R T Daly
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | | | - E Mazarico
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - B Rozitis
- School of Physical Sciences, Open University, Milton Keynes, UK
| | - A J Ryan
- KinetX Inc., Simi Valley, CA, USA
| | - D N DellaGiustina
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - B Rizk
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | - H L Enos
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - D S Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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6
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Molaro JL, Walsh KJ, Jawin ER, Ballouz RL, Bennett CA, DellaGiustina DN, Golish DR, Drouet d'Aubigny C, Rizk B, Schwartz SR, Hanna RD, Martel SJ, Pajola M, Campins H, Ryan AJ, Bottke WF, Lauretta DS. In situ evidence of thermally induced rock breakdown widespread on Bennu's surface. Nat Commun 2020; 11:2913. [PMID: 32518333 PMCID: PMC7283247 DOI: 10.1038/s41467-020-16528-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 05/04/2020] [Indexed: 11/13/2022] Open
Abstract
Rock breakdown due to diurnal thermal cycling has been hypothesized to drive boulder degradation and regolith production on airless bodies. Numerous studies have invoked its importance in driving landscape evolution, yet morphological features produced by thermal fracture processes have never been definitively observed on an airless body, or any surface where other weathering mechanisms may be ruled out. The Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) mission provides an opportunity to search for evidence of thermal breakdown and assess its significance on asteroid surfaces. Here we show boulder morphologies observed on Bennu that are consistent with terrestrial observations and models of fatigue-driven exfoliation and demonstrate how crack propagation via thermal stress can lead to their development. The rate and expression of this process will vary with asteroid composition and location, influencing how different bodies evolve and their apparent relative surface ages from space weathering and cratering records. In their study, the authors discuss the potential of thermal weathering on airless bodies. As a case study, they use boulder and fracture morphologies on asteroid Bennu.
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Affiliation(s)
- J L Molaro
- Planetary Science Institute, 1700 E Ft Lowell Rd., STE 106, Tucson, AZ, 85719, USA.
| | - K J Walsh
- Southwest Research Institute, 1050 Walnut St #300, Boulder, CO, 80302, USA
| | - E R Jawin
- Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, PO Box 37012, MRC 119, Washington, D.C, 20013, USA
| | - R-L Ballouz
- Lunar and Planetary Laboratory, University of Arizona, 1629 E University Blvd, Tucson, AZ, 85721, USA
| | - C A Bennett
- Lunar and Planetary Laboratory, University of Arizona, 1629 E University Blvd, Tucson, AZ, 85721, USA
| | - D N DellaGiustina
- Lunar and Planetary Laboratory, University of Arizona, 1629 E University Blvd, Tucson, AZ, 85721, USA
| | - D R Golish
- Lunar and Planetary Laboratory, University of Arizona, 1629 E University Blvd, Tucson, AZ, 85721, USA
| | - C Drouet d'Aubigny
- Lunar and Planetary Laboratory, University of Arizona, 1629 E University Blvd, Tucson, AZ, 85721, USA
| | - B Rizk
- Lunar and Planetary Laboratory, University of Arizona, 1629 E University Blvd, Tucson, AZ, 85721, USA
| | - S R Schwartz
- Lunar and Planetary Laboratory, University of Arizona, 1629 E University Blvd, Tucson, AZ, 85721, USA
| | - R D Hanna
- Department of Geological Sciences, Jackson School of Geosciences, University of Texas, 2305 Speedway Stop C1160, Austin, TX, 78712, USA
| | - S J Martel
- Department of Earth Sciences, School of Ocean and Earth Science and Technology, University of Hawai'i at Mānoa, POST Building STE 701, 1680 East-West Road, Honolulu, HI, 96822, USA
| | - M Pajola
- INAF-Astronomical Observatory of Padova, Vic. Osservatorio 5, 35122, Padova, Italy
| | - H Campins
- Department of Physics, University of Central Florida, 4111 Libra Drive, Physical Sciences Bldg. 430, Orlando, FL, 32816, USA
| | - A J Ryan
- Lunar and Planetary Laboratory, University of Arizona, 1629 E University Blvd, Tucson, AZ, 85721, USA
| | - W F Bottke
- Southwest Research Institute, 1050 Walnut St #300, Boulder, CO, 80302, USA
| | - D S Lauretta
- Lunar and Planetary Laboratory, University of Arizona, 1629 E University Blvd, Tucson, AZ, 85721, USA
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7
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Michel P, Ballouz RL, Barnouin OS, Jutzi M, Walsh KJ, May BH, Manzoni C, Richardson DC, Schwartz SR, Sugita S, Watanabe S, Miyamoto H, Hirabayashi M, Bottke WF, Connolly HC, Yoshikawa M, Lauretta DS. Collisional formation of top-shaped asteroids and implications for the origins of Ryugu and Bennu. Nat Commun 2020; 11:2655. [PMID: 32461569 PMCID: PMC7253434 DOI: 10.1038/s41467-020-16433-z] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 04/29/2020] [Indexed: 11/24/2022] Open
Abstract
Asteroid shapes and hydration levels can serve as tracers of their history and origin. For instance, the asteroids (162173) Ryugu and (101955) Bennu have an oblate spheroidal shape with a pronounced equator, but contain different surface hydration levels. Here we show, through numerical simulations of large asteroid disruptions, that oblate spheroids, some of which have a pronounced equator defining a spinning top shape, can form directly through gravitational reaccumulation. We further show that rubble piles formed in a single disruption can have similar porosities but variable degrees of hydration. The direct formation of top shapes from single disruption alone can explain the relatively old crater-retention ages of the equatorial features of Ryugu and Bennu. Two separate parent-body disruptions are not necessarily required to explain their different hydration levels.
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Affiliation(s)
- P Michel
- Universite Côte d'Azur, Observatoire de la Côte d'Azur, Centre National de la Recherche Scientifique, Laboratoire Lagrange, Nice, France.
| | - 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
| | - M Jutzi
- Physics Institute, University of Bern, NCCR PlanetS, Gesellsschaftsstrasse 6, 3012, Bern, Switzerland
| | - K J Walsh
- Southwest Research Institute, Boulder, CO, USA
| | - B H May
- London Stereoscopic Company, London, UK
| | - C Manzoni
- London Stereoscopic Company, London, UK
| | - D C Richardson
- Department of Astronomy, University of Maryland, College Park, MD, USA
| | - S R Schwartz
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - S Sugita
- Department of Earth and Planetary Science, School of Science, The University of Tokyo, Tokyo, Japan
| | - S Watanabe
- Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan
| | - H Miyamoto
- Department of System Innovation, School of Engineering, The University of Tokyo, Tokyo, Japan
| | - M Hirabayashi
- Department of Aerospace Engineering, Auburn University, Auburn, AL, USA
| | - W F Bottke
- Southwest Research Institute, Boulder, CO, USA
| | - H C Connolly
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
- Department of Geology, School of Earth and Environment, Rowan University, Glassboro, NJ, USA
| | - M Yoshikawa
- Institute of Space and Astronautical Sciences, JAXA, Sagamihara, Japan
| | - D S Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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8
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Lauretta DS, Hergenrother CW, Chesley SR, Leonard JM, Pelgrift JY, Adam CD, Al Asad M, Antreasian PG, Ballouz RL, Becker KJ, Bennett CA, Bos BJ, Bottke WF, Brozović M, Campins H, Connolly HC, Daly MG, Davis AB, de León J, DellaGiustina DN, Drouet d'Aubigny CY, Dworkin JP, Emery JP, Farnocchia D, Glavin DP, Golish DR, Hartzell CM, Jacobson RA, Jawin ER, Jenniskens P, Kidd JN, Lessac-Chenen EJ, Li JY, Libourel G, Licandro J, Liounis AJ, Maleszewski CK, Manzoni C, May B, McCarthy LK, McMahon JW, Michel P, Molaro JL, Moreau MC, Nelson DS, Owen WM, Rizk B, Roper HL, Rozitis B, Sahr EM, Scheeres DJ, Seabrook JA, Selznick SH, Takahashi Y, Thuillet F, Tricarico P, Vokrouhlický D, Wolner CWV. Episodes of particle ejection from the surface of the active asteroid (101955) Bennu. Science 2020; 366:366/6470/eaay3544. [PMID: 31806784 DOI: 10.1126/science.aay3544] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 10/22/2019] [Indexed: 11/02/2022]
Abstract
Active asteroids are those that show evidence of ongoing mass loss. We report repeated instances of particle ejection from the surface of (101955) Bennu, demonstrating that it is an active asteroid. The ejection events were imaged by the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) spacecraft. For the three largest observed events, we estimated the ejected particle velocities and sizes, event times, source regions, and energies. We also determined the trajectories and photometric properties of several gravitationally bound particles that orbited temporarily in the Bennu environment. We consider multiple hypotheses for the mechanisms that lead to particle ejection for the largest events, including rotational disruption, electrostatic lofting, ice sublimation, phyllosilicate dehydration, meteoroid impacts, thermal stress fracturing, and secondary impacts.
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Affiliation(s)
- D S Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA.
| | - C W Hergenrother
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA.
| | - S R Chesley
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | | | - C D Adam
- KinetX Aerospace, Simi Valley, CA, USA
| | - M Al Asad
- Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada
| | | | - R-L Ballouz
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - K J 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
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - W F Bottke
- Southwest Research Institute, Boulder, CO, USA
| | - M Brozović
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - H Campins
- Department of Physics, University of Central Florida, Orlando, FL, USA
| | - H C Connolly
- Department of Geology, Rowan University, Glassboro, NJ, USA.,Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - M G Daly
- The Centre for Research in Earth and Space Science, York University, Toronto, ON, Canada
| | - A B Davis
- Smead Department of Aerospace Engineering Sciences, University of Colorado, Boulder, CO, USA
| | - J de León
- Instituto de Astrofísica de Canarias and Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain
| | - D N DellaGiustina
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA.,Department of Geosciences, University of Arizona, Tucson, AZ, USA
| | | | - J P Dworkin
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - J P Emery
- Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN, USA.,Department of Astronomy and Planetary Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - D Farnocchia
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - D P Glavin
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - D R Golish
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - C M Hartzell
- Department of Aerospace Engineering, University of Maryland, College Park, MD, USA
| | - R A Jacobson
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - E R Jawin
- Smithsonian Institution National Museum of Natural History, Washington, DC, USA
| | - P Jenniskens
- SETI (Search for Extraterrestrial Intelligence) Institute, Mountain View, CA, USA
| | - J N Kidd
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | - J-Y Li
- Planetary Science Institute, Tucson, AZ, USA
| | - G Libourel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS (Centre national de la recherche scientifique), Laboratoire Lagrange, Nice, France
| | - J Licandro
- Instituto de Astrofísica de Canarias and Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain
| | - A J Liounis
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - C K Maleszewski
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - C Manzoni
- London Stereoscopic Company, London, UK
| | - B May
- London Stereoscopic Company, London, UK
| | | | - J W McMahon
- Smead Department of Aerospace Engineering Sciences, University of Colorado, Boulder, CO, USA
| | - P Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS (Centre national de la recherche scientifique), Laboratoire Lagrange, Nice, France
| | - J L Molaro
- Planetary Science Institute, Tucson, AZ, USA
| | - M C Moreau
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | | | - W M Owen
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - B Rizk
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - H L Roper
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - B Rozitis
- School of Physical Sciences, Open University, Milton Keynes, UK
| | - E M Sahr
- KinetX Aerospace, Simi Valley, CA, USA
| | - D J Scheeres
- Smead Department of Aerospace Engineering Sciences, University of Colorado, Boulder, CO, USA
| | - J A Seabrook
- The Centre for Research in Earth and Space Science, York University, Toronto, ON, Canada
| | - S H Selznick
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - Y Takahashi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - F Thuillet
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS (Centre national de la recherche scientifique), Laboratoire Lagrange, Nice, France
| | - P Tricarico
- Planetary Science Institute, Tucson, AZ, USA
| | - D Vokrouhlický
- Institute of Astronomy, Charles University, Prague, Czech Republic
| | - C W V Wolner
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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9
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Scheeres DJ, McMahon JW, French AS, Brack DN, Chesley SR, Farnocchia D, Takahashi Y, Leonard JM, Geeraert J, Page B, Antreasian P, Getzandanner K, Rowlands D, Mazarico E, Small J, Highsmith DE, Moreau M, Emery JP, Rozitis B, Hirabayashi M, Sánchez P, Wal SV, Tricarico P, Ballouz RL, Johnson CL, Asad MMA, Susorney HCM, Barnouin OS, Daly MG, Seabrook J, Gaskell RW, Palmer EE, Weirich JR, Walsh KJ, Jawin ER, Bierhaus EB, Michel P, Bottke WF, Nolan MC, Connolly HC, Lauretta DS. The dynamic geophysical environment of (101955) Bennu based on OSIRIS-REx measurements. Nat Astron 2019; 3:352-361. [PMID: 32601603 PMCID: PMC7323631 DOI: 10.1038/s41550-019-0721-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 02/11/2019] [Indexed: 05/18/2023]
Abstract
The top-shape morphology of asteroid (101955) Bennu is commonly found among fast-spinning asteroids and binary asteroid primaries, and might have contributed significantly to binary asteroid formation. Yet a detailed geophysical analysis of this morphology for a fast-spinning asteroid has not been possible prior to the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) mission. Combining the measured Bennu mass and shape obtained during the Preliminary Survey phase of OSIRIS-REx, we find a significant transition in Bennu's surface slopes within its rotational Roche lobe, defined as the region where material is energetically trapped to the surface. As the intersection of the rotational Roche lobe with Bennu's surface has been most recently migrating towards its equator (given Bennu's increasing spin rate), we infer that Bennu's surface slopes have been changing across its surface within the last million years. We also find evidence for substantial density heterogeneity within this body, suggesting that its interior has a distribution of voids and boulders. The presence of such heterogeneity and Bennu's top-shape is consistent with spin-induced failure at some point in its past, although the manner of its failure cannot be determined yet. Future measurements by the OSIRIS-REx spacecraft will give additional insights and may resolve questions regarding the formation and evolution of Bennu's top-shape morphology and its link to the formation of binary asteroids.
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Affiliation(s)
- D J Scheeres
- Smead Department of Aerospace Engineering, University of Colorado, Boulder, CO, USA
| | - J W McMahon
- Smead Department of Aerospace Engineering, University of Colorado, Boulder, CO, USA
| | - A S French
- Smead Department of Aerospace Engineering, University of Colorado, Boulder, CO, USA
| | - D N Brack
- Smead Department of Aerospace Engineering, University of Colorado, Boulder, CO, USA
| | - S R Chesley
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - D Farnocchia
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Y Takahashi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - J M Leonard
- KinetX Aerospace, Inc., Simi Valley, CA, USA
| | - J Geeraert
- KinetX Aerospace, Inc., Simi Valley, CA, USA
| | - B Page
- KinetX Aerospace, Inc., Simi Valley, CA, USA
| | | | | | - D Rowlands
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - E Mazarico
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - J Small
- Aerospace Corporation, Chantilly, VA, USA
| | | | - M Moreau
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - J P Emery
- University of Tennessee, Knoxville, TN, USA
| | - B Rozitis
- Planetary and Space Sciences, School of Physical Sciences, The Open University, Milton Keynes, UK
| | | | - P Sánchez
- Colorado Center for Astrodynamics Research, University of Colorado, Boulder, CO, USA
| | - S Van Wal
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Japan
| | - P Tricarico
- Planetary Science Institute, Tucson, AZ, USA
| | - R-L Ballouz
- Lunar Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - C L Johnson
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
- Planetary Science Institute, Tucson, AZ, USA
| | - M M Al Asad
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - H C M Susorney
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - 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, ON, Canada
| | - J Seabrook
- The Centre for Research in Earth and Space Science, York University, Toronto, ON, Canada
| | - R W Gaskell
- Planetary Science Institute, Tucson, AZ, USA
| | - E E Palmer
- Planetary Science Institute, Tucson, AZ, USA
| | - J R Weirich
- Planetary Science Institute, Tucson, AZ, USA
| | - K J Walsh
- Southwest Research Institute, Boulder, CO, USA
| | - E R Jawin
- Smithsonian Institution National Museum of Natural History, Washington, DC, USA
| | - E B Bierhaus
- Lockheed Martin Space Systems Company, Denver, CO, USA
| | - P Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - W F Bottke
- Southwest Research Institute, Boulder, CO, USA
| | - M C Nolan
- Lunar Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - H C Connolly
- School of Earth and Environment, Rowan University, Glassboro, NJ, USA
| | - D S Lauretta
- Lunar Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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10
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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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11
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Sugita S, Honda R, Morota T, Kameda S, Sawada H, Tatsumi E, Yamada M, Honda C, Yokota Y, Kouyama T, Sakatani N, Ogawa K, Suzuki H, Okada T, Namiki N, Tanaka S, Iijima Y, Yoshioka K, Hayakawa M, Cho Y, Matsuoka M, Hirata N, Hirata N, Miyamoto H, Domingue D, Hirabayashi M, Nakamura T, Hiroi T, Michikami T, Michel P, Ballouz RL, Barnouin OS, Ernst CM, Schröder SE, Kikuchi H, Hemmi R, Komatsu G, Fukuhara T, Taguchi M, Arai T, Senshu H, Demura H, Ogawa Y, Shimaki Y, Sekiguchi T, Müller TG, Hagermann A, Mizuno T, Noda H, Matsumoto K, Yamada R, Ishihara Y, Ikeda H, Araki H, Yamamoto K, Abe S, Yoshida F, Higuchi A, Sasaki S, Oshigami S, Tsuruta S, Asari K, Tazawa S, Shizugami M, Kimura J, Otsubo T, Yabuta H, Hasegawa S, Ishiguro M, Tachibana S, Palmer E, Gaskell R, Le Corre L, Jaumann R, Otto K, Schmitz N, Abell PA, Barucci MA, Zolensky ME, Vilas F, Thuillet F, Sugimoto C, Takaki N, Suzuki Y, Kamiyoshihara H, Okada M, Nagata K, Fujimoto M, Yoshikawa M, Yamamoto Y, Shirai K, Noguchi R, Ogawa N, Terui F, Kikuchi S, Yamaguchi T, Oki Y, Takao Y, Takeuchi H, Ono G, Mimasu Y, Yoshikawa K, Takahashi T, Takei Y, Fujii A, Hirose C, Nakazawa S, Hosoda S, Mori O, Shimada T, Soldini S, Iwata T, Abe M, Yano H, Tsukizaki R, Ozaki M, Nishiyama K, Saiki T, Watanabe S, Tsuda Y. The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes. Science 2019; 364:252. [PMID: 30890587 DOI: 10.1126/science.aaw0422] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/12/2019] [Indexed: 11/02/2022]
Abstract
The near-Earth carbonaceous asteroid 162173 Ryugu is thought to have been produced from a parent body that contained water ice and organic molecules. The Hayabusa2 spacecraft has obtained global multicolor images of Ryugu. Geomorphological features present include a circum-equatorial ridge, east-west dichotomy, high boulder abundances across the entire surface, and impact craters. Age estimates from the craters indicate a resurfacing age of [Formula: see text] years for the top 1-meter layer. Ryugu is among the darkest known bodies in the Solar System. The high abundance and spectral properties of boulders are consistent with moderately dehydrated materials, analogous to thermally metamorphosed meteorites found on Earth. The general uniformity in color across Ryugu's surface supports partial dehydration due to internal heating of the asteroid's parent body.
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Affiliation(s)
- S Sugita
- The University of Tokyo, Tokyo 113-0033, Japan. .,Planetary Exploration Research Center, Chiba Institute of Technology, Narashino 275-0016, Japan
| | - R Honda
- Kochi University, Kochi 780-8520, Japan
| | - T Morota
- Nagoya University, Nagoya 464-8601, Japan
| | - S Kameda
- Rikkyo University, Tokyo 171-8501, Japan
| | - H Sawada
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - E Tatsumi
- The University of Tokyo, Tokyo 113-0033, Japan
| | - M Yamada
- Planetary Exploration Research Center, Chiba Institute of Technology, Narashino 275-0016, Japan
| | - C Honda
- University of Aizu, Aizu-Wakamatsu 965-8580, Japan
| | - Y Yokota
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan.,Kochi University, Kochi 780-8520, Japan
| | - T Kouyama
- National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064 Japan
| | - N Sakatani
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - K Ogawa
- Kobe University, Kobe 657-8501, Japan
| | - H Suzuki
- Meiji University, Kawasaki 214-8571, Japan
| | - T Okada
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan.,The University of Tokyo, Tokyo 113-0033, Japan
| | - N Namiki
- National Astronomical Observatory of Japan, Mitaka 181-8588, Japan.,SOKENDAI (The Graduate University for Advanced Studies), Hayama 240-0193, Japan
| | - S Tanaka
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan.,SOKENDAI (The Graduate University for Advanced Studies), Hayama 240-0193, Japan
| | - Y Iijima
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - K Yoshioka
- The University of Tokyo, Tokyo 113-0033, Japan
| | - M Hayakawa
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - Y Cho
- The University of Tokyo, Tokyo 113-0033, Japan
| | - M Matsuoka
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - N Hirata
- University of Aizu, Aizu-Wakamatsu 965-8580, Japan
| | - N Hirata
- Kobe University, Kobe 657-8501, Japan
| | - H Miyamoto
- The University of Tokyo, Tokyo 113-0033, Japan
| | - D Domingue
- Planetary Science Institute, Tucson, AZ 85719, USA
| | | | - T Nakamura
- Tohoku University, Sendai 980-8578, Japan
| | - T Hiroi
- Brown University, Providence, RI 02912, USA
| | - T Michikami
- Kindai University, Higashi-Hiroshima 739-2116, Japan
| | - P Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, Centre National de le Recherche Scientifique (CNRS), Laboratoire Lagrange, 06304 Nice, France
| | - R-L Ballouz
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan.,University of Arizona, Tucson, AZ 85705, USA
| | - O S Barnouin
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - C M Ernst
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - S E Schröder
- German Aerospace Center (DLR), Institute of Planetary Research, 12489 Berlin, Germany
| | - H Kikuchi
- The University of Tokyo, Tokyo 113-0033, Japan
| | - R Hemmi
- The University of Tokyo, Tokyo 113-0033, Japan
| | - G Komatsu
- International Research School of Planetary Sciences, Università d'Annunzio, 65127 Pescara, Italy.,Planetary Exploration Research Center, Chiba Institute of Technology, Narashino 275-0016, Japan
| | - T Fukuhara
- Rikkyo University, Tokyo 171-8501, Japan
| | - M Taguchi
- Rikkyo University, Tokyo 171-8501, Japan
| | - T Arai
- Ashikaga University, Ashikaga 326-8558, Japan
| | - H Senshu
- Planetary Exploration Research Center, Chiba Institute of Technology, Narashino 275-0016, Japan
| | - H Demura
- University of Aizu, Aizu-Wakamatsu 965-8580, Japan
| | - Y Ogawa
- University of Aizu, Aizu-Wakamatsu 965-8580, Japan
| | - Y Shimaki
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - T Sekiguchi
- Hokkaido University of Education, Asahikawa 070-8621, Japan
| | - T G Müller
- Max-Planck-Institut für Extraterrestrische Physik, 85748 Garching, Germany
| | - A Hagermann
- University of Stirling, FK9 4LA, Scotland, UK
| | - T Mizuno
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - H Noda
- National Astronomical Observatory of Japan, Mitaka 181-8588, Japan
| | - K Matsumoto
- National Astronomical Observatory of Japan, Mitaka 181-8588, Japan.,SOKENDAI (The Graduate University for Advanced Studies), Hayama 240-0193, Japan
| | - R Yamada
- University of Aizu, Aizu-Wakamatsu 965-8580, Japan
| | - Y Ishihara
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - H Ikeda
- Research and Development Directorate, JAXA, Sagamihara 252-5210, Japan
| | - H Araki
- National Astronomical Observatory of Japan, Mitaka 181-8588, Japan
| | - K Yamamoto
- National Astronomical Observatory of Japan, Mitaka 181-8588, Japan
| | - S Abe
- Nihon University, Funabashi 274-8501, Japan
| | - F Yoshida
- Planetary Exploration Research Center, Chiba Institute of Technology, Narashino 275-0016, Japan
| | - A Higuchi
- National Astronomical Observatory of Japan, Mitaka 181-8588, Japan
| | - S Sasaki
- Osaka University, Toyonaka 560-0043, Japan
| | - S Oshigami
- National Astronomical Observatory of Japan, Mitaka 181-8588, Japan
| | - S Tsuruta
- National Astronomical Observatory of Japan, Mitaka 181-8588, Japan
| | - K Asari
- National Astronomical Observatory of Japan, Mitaka 181-8588, Japan
| | - S Tazawa
- National Astronomical Observatory of Japan, Mitaka 181-8588, Japan
| | - M Shizugami
- National Astronomical Observatory of Japan, Mitaka 181-8588, Japan
| | - J Kimura
- Osaka University, Toyonaka 560-0043, Japan
| | - T Otsubo
- Hitotsubashi University, Tokyo 186-8601, Japan
| | - H Yabuta
- Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - S Hasegawa
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - M Ishiguro
- Seoul National University, Seoul 08826, Korea
| | - S Tachibana
- The University of Tokyo, Tokyo 113-0033, Japan
| | - E Palmer
- Planetary Science Institute, Tucson, AZ 85719, USA
| | - R Gaskell
- Planetary Science Institute, Tucson, AZ 85719, USA
| | - L Le Corre
- Planetary Science Institute, Tucson, AZ 85719, USA
| | - R Jaumann
- German Aerospace Center (DLR), Institute of Planetary Research, 12489 Berlin, Germany
| | - K Otto
- German Aerospace Center (DLR), Institute of Planetary Research, 12489 Berlin, Germany
| | - N Schmitz
- German Aerospace Center (DLR), Institute of Planetary Research, 12489 Berlin, Germany
| | - P A Abell
- NASA Johnson Space Center, Houston, TX 77058, USA
| | - M A Barucci
- Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique (LESIA)-Observatoire de Paris, Paris Sciences et Lettres (PSL), Centre National de le Recherche Scientifique (CNRS), Sorbonne Université, Université Paris-Diderot, 92195 Meudon Principal Cedex, France
| | - M E Zolensky
- NASA Johnson Space Center, Houston, TX 77058, USA
| | - F Vilas
- Planetary Science Institute, Tucson, AZ 85719, USA
| | - F Thuillet
- Université Côte d'Azur, Observatoire de la Côte d'Azur, Centre National de le Recherche Scientifique (CNRS), Laboratoire Lagrange, 06304 Nice, France
| | - C Sugimoto
- The University of Tokyo, Tokyo 113-0033, Japan
| | - N Takaki
- The University of Tokyo, Tokyo 113-0033, Japan
| | - Y Suzuki
- The University of Tokyo, Tokyo 113-0033, Japan
| | | | - M Okada
- The University of Tokyo, Tokyo 113-0033, Japan
| | - K Nagata
- National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064 Japan
| | - M Fujimoto
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - M Yoshikawa
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan.,SOKENDAI (The Graduate University for Advanced Studies), Hayama 240-0193, Japan
| | - Y Yamamoto
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan.,SOKENDAI (The Graduate University for Advanced Studies), Hayama 240-0193, Japan
| | - K Shirai
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - R Noguchi
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - N Ogawa
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - F Terui
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - S Kikuchi
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - T Yamaguchi
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - Y Oki
- The University of Tokyo, Tokyo 113-0033, Japan
| | - Y Takao
- The University of Tokyo, Tokyo 113-0033, Japan
| | - H Takeuchi
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - G Ono
- Research and Development Directorate, JAXA, Sagamihara 252-5210, Japan
| | - Y Mimasu
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - K Yoshikawa
- Research and Development Directorate, JAXA, Sagamihara 252-5210, Japan
| | - T Takahashi
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - Y Takei
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan.,Research and Development Directorate, JAXA, Sagamihara 252-5210, Japan
| | - A Fujii
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - C Hirose
- Research and Development Directorate, JAXA, Sagamihara 252-5210, Japan
| | - S Nakazawa
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - S Hosoda
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - O Mori
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - T Shimada
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - S Soldini
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - T Iwata
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan.,SOKENDAI (The Graduate University for Advanced Studies), Hayama 240-0193, Japan
| | - M Abe
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan.,SOKENDAI (The Graduate University for Advanced Studies), Hayama 240-0193, Japan
| | - H Yano
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan.,SOKENDAI (The Graduate University for Advanced Studies), Hayama 240-0193, Japan
| | - R Tsukizaki
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - M Ozaki
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan.,SOKENDAI (The Graduate University for Advanced Studies), Hayama 240-0193, Japan
| | - K Nishiyama
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - T Saiki
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - S Watanabe
- Nagoya University, Nagoya 464-8601, Japan.,Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - Y Tsuda
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan.,SOKENDAI (The Graduate University for Advanced Studies), Hayama 240-0193, Japan
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