1
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Pajola M, Tusberti F, Lucchetti A, Barnouin O, Cambioni S, Ernst CM, Dotto E, Daly RT, Poggiali G, Hirabayashi M, Nakano R, Epifani EM, Chabot NL, Della Corte V, Rivkin A, Agrusa H, Zhang Y, Penasa L, Ballouz RL, Ivanovski S, Murdoch N, Rossi A, Robin C, Ieva S, Vincent JB, Ferrari F, Raducan SD, Campo-Bagatin A, Parro L, Benavidez P, Tancredi G, Karatekin Ö, Trigo-Rodriguez JM, Sunshine J, Farnham T, Asphaug E, Deshapriya JDP, Hasselmann PHA, Beccarelli J, Schwartz SR, Abell P, Michel P, Cheng A, Brucato JR, Zinzi A, Amoroso M, Pirrotta S, Impresario G, Bertini I, Capannolo A, Caporali S, Ceresoli M, Cremonese G, Dall'Ora M, Gai I, Casajus LG, Gramigna E, Manghi RL, Lavagna M, Lombardo M, Modenini D, Palumbo P, Perna D, Tortora P, Zannoni M, Zanotti G. Evidence for multi-fragmentation and mass shedding of boulders on rubble-pile binary asteroid system (65803) Didymos. Nat Commun 2024; 15:6205. [PMID: 39080257 PMCID: PMC11289111 DOI: 10.1038/s41467-024-50148-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 07/02/2024] [Indexed: 08/02/2024] Open
Abstract
Asteroids smaller than 10 km are thought to be rubble piles formed from the reaccumulation of fragments produced in the catastrophic disruption of parent bodies. Ground-based observations reveal that some of these asteroids are today binary systems, in which a smaller secondary orbits a larger primary asteroid. However, how these asteroids became binary systems remains unclear. Here, we report the analysis of boulders on the surface of the stony asteroid (65803) Didymos and its moonlet, Dimorphos, from data collected by the NASA DART mission. The size-frequency distribution of boulders larger than 5 m on Dimorphos and larger than 22.8 m on Didymos confirms that both asteroids are piles of fragments produced in the catastrophic disruption of their progenitors. Dimorphos boulders smaller than 5 m have size best-fit by a Weibull distribution, which we attribute to a multi-phase fragmentation process either occurring during coalescence or during surface evolution. The density per km2 of Dimorphos boulders ≥1 m is 2.3x with respect to the one obtained for (101955) Bennu, while it is 3.0x with respect to (162173) Ryugu. Such values increase once Dimorphos boulders ≥5 m are compared with Bennu (3.5x), Ryugu (3.9x) and (25143) Itokawa (5.1x). This is of interest in the context of asteroid studies because it means that contrarily to the single bodies visited so far, binary systems might be affected by subsequential fragmentation processes that largely increase their block density per km2. Direct comparison between the surface distribution and shapes of the boulders on Didymos and Dimorphos suggest that the latter inherited its material from the former. This finding supports the hypothesis that some asteroid binary systems form through the spin up and mass shedding of a fraction of the primary asteroid.
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Affiliation(s)
- M Pajola
- INAF-Astronomical Observatory of Padova, Padova, Italy.
| | - F Tusberti
- INAF-Astronomical Observatory of Padova, Padova, Italy
| | - A Lucchetti
- INAF-Astronomical Observatory of Padova, Padova, Italy
| | - O Barnouin
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - S Cambioni
- Department of Earth, Atmospheric and Planetary Sciences, Massachussets Institute of Technology, Cambridge, MA, USA
| | - C M Ernst
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - E Dotto
- INAF-Osservatorio Astronomico di Roma, Roma, Italy
| | - R T Daly
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - G Poggiali
- INAF-Osservatorio Astrofisico di Arcetri, Firenze, Italy
- LESIA-Observatorie de Paris PSL, Paris, France
| | | | - R Nakano
- Georgia Institute of Technology, Atlanta, GA, USA
- Department of Aerospace Engineering, Auburn University, Auburn, AL, USA
| | | | - N L Chabot
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - V Della Corte
- INAF-Osservatorio Astronomico di Capodimonte, Napoli, Italy
| | - A Rivkin
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - H Agrusa
- Department of Astronomy, University of Maryland, College Park, MD, USA
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - Y Zhang
- Climate & Space Sciences and Engineering, University of Michigan, Hayward, MI, USA
| | - L Penasa
- INAF-Astronomical Observatory of Padova, Padova, Italy
| | - R-L Ballouz
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - S Ivanovski
- INAF-Osservatorio Astronomico di Trieste, Trieste, Italy
| | - N Murdoch
- Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de, Toulouse, France
| | - A Rossi
- IFAC-CNR, Sesto Fiorentino, Firenze, Italy
| | - C Robin
- Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de, Toulouse, France
| | - S Ieva
- INAF-Osservatorio Astronomico di Roma, Roma, Italy
| | | | - F Ferrari
- Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano-Bovisa Campus, Milano, Italy
| | - S D Raducan
- Space Research and Planetary Sciences, Physikalisches Institut, University of Bern, Bern, Switzerland
| | | | - L Parro
- Universidad de Alicante, de Alicante, Spain
- University of Arizona, Tucson, AZ, USA
| | | | - G Tancredi
- Dpto. Astronomia, Facultad Ciencias Igua, Montevideo, Uruguay
| | - Ö Karatekin
- Royal Observatory of Belgium, Uccle, Belgium
| | - J M Trigo-Rodriguez
- Institute of Space Sciences (ICE, CSIC) and Institut d'Estudis Espacials de Catalunya (IEEC), Barcelona, Spain
| | - J Sunshine
- Department of Astronomy, University of Maryland, College Park, MD, USA
| | - T Farnham
- Department of Astronomy, University of Maryland, College Park, MD, USA
| | - E Asphaug
- Planetary Science Institute; University of Arizona, Tucson, AZ, USA
| | | | | | - J Beccarelli
- INAF-Astronomical Observatory of Padova, Padova, Italy
| | - S R Schwartz
- Planetary Science Institute; University of Arizona, Tucson, AZ, USA
| | - P Abell
- NASA Johnson Space Center, Houston, TX, USA
| | - P Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
- Department of Systems Innovation, School of Engineering, The University of Tokyo, Tokyo, Japan
| | - A Cheng
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - J R Brucato
- INAF-Osservatorio Astrofisico di Arcetri, Firenze, Italy
| | - A Zinzi
- Agenzia Spaziale Italiana, Roma, Italy
- Space Science Data Center-ASI, Roma, Italy
| | - M Amoroso
- Agenzia Spaziale Italiana, Roma, Italy
| | | | | | - I Bertini
- Dipartimento di Scienze & Tecnologie, Università degli Studi di Napoli "Parthenope", Napoli, Italy
| | - A Capannolo
- Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de, Toulouse, France
| | - S Caporali
- INAF-Osservatorio Astrofisico di Arcetri, Firenze, Italy
| | - M Ceresoli
- Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano-Bovisa Campus, Milano, Italy
| | - G Cremonese
- INAF-Astronomical Observatory of Padova, Padova, Italy
| | - M Dall'Ora
- INAF-Osservatorio Astronomico di Capodimonte, Napoli, Italy
| | - I Gai
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - L Gomez Casajus
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - E Gramigna
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - R Lasagni Manghi
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - M Lavagna
- Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano-Bovisa Campus, Milano, Italy
| | - M Lombardo
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - D Modenini
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - P Palumbo
- INAF-Istituto di Astrofisica e Planetologia Spaziali, Roma, Italy
| | - D Perna
- INAF-Osservatorio Astronomico di Roma, Roma, Italy
| | - P Tortora
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - M Zannoni
- Dipartimento di Ingegneria Industriale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
- Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum-Università di Bologna, Forlì, Italy
| | - G Zanotti
- Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano-Bovisa Campus, Milano, Italy
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Bigot J, Lombardo P, Murdoch N, Scheeres DJ, Vivet D, Zhang Y, Sunshine J, Vincent JB, Barnouin OS, Ernst CM, Daly RT, Sunday C, Michel P, Campo-Bagatin A, Lucchetti A, Pajola M, Rivkin AS, Chabot NL. The bearing capacity of asteroid (65803) Didymos estimated from boulder tracks. Nat Commun 2024; 15:6204. [PMID: 39080000 PMCID: PMC11289458 DOI: 10.1038/s41467-024-50149-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 05/14/2024] [Indexed: 08/02/2024] Open
Abstract
The bearing capacity - the ability of a surface to support applied loads - is an important parameter for understanding and predicting the response of a surface. Previous work has inferred the bearing capacity and trafficability of specific regions of the Moon using orbital imagery and measurements of the boulder tracks visible on its surface. Here, we estimate the bearing capacity of the surface of an asteroid for the first time using DART/DRACO images of suspected boulder tracks on the surface of asteroid (65803) Didymos. Given the extremely low surface gravity environment, special attention is paid to the underlying assumptions of the geotechnical approach. The detailed analysis of the boulder tracks indicates that the boulders move from high to low gravitational potential, and provides constraints on whether the boulders may have ended their surface motion by entering a ballistic phase. From the 9 tracks identified with sufficient resolution to estimate their dimensions, we find an average boulder track width and length of 8.9 ± 1.5 m and 51.6 ± 13.3 m, respectively. From the track widths, the mean bearing capacity of Didymos is estimated to be 70 N/m2, implying that every 1 m2 of Didymos' surface at the track location can support only ~70 N of force before experiencing general shear failure. This value is at least 3 orders of magnitude less than the bearing capacity of dry sand on Earth, or lunar regolith.
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Affiliation(s)
- J Bigot
- Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de Toulouse, Toulouse, France
| | - P Lombardo
- Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de Toulouse, Toulouse, France
| | - N Murdoch
- Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de Toulouse, Toulouse, France.
| | | | - D Vivet
- Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de Toulouse, Toulouse, France
| | - Y Zhang
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA
| | - J Sunshine
- University of Maryland, College Park, MD, USA
| | | | - O S Barnouin
- Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA
| | - C M Ernst
- Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA
| | - R T Daly
- Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA
| | - C Sunday
- University of Maryland, College Park, MD, USA
| | - P Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | | | - A Lucchetti
- INAF-OAPD Astronomical Observatory of Padova, Padova, Italy
| | - M Pajola
- INAF-OAPD Astronomical Observatory of Padova, Padova, Italy
| | - A S Rivkin
- Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA
| | - N L Chabot
- Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA
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3
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Walsh KJ, Ballouz RL, Bottke WF, Avdellidou C, Connolly HC, Delbo M, DellaGiustina DN, Jawin ER, McCoy T, Michel P, Morota T, Nolan MC, Schwartz SR, Sugita S, Lauretta DS. Numerical simulations suggest asteroids (101955) Bennu and (162173) Ryugu are likely second or later generation rubble piles. Nat Commun 2024; 15:5653. [PMID: 38969628 PMCID: PMC11226714 DOI: 10.1038/s41467-024-49310-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 05/29/2024] [Indexed: 07/07/2024] Open
Abstract
Rubble pile asteroids are widely understood to be composed of reaccumulated debris following a catastrophic collision between asteroids in the main asteroid belt, where each disruption can make a family of new asteroids. Near-Earth asteroids Ryugu and Bennu have been linked to collisional families in the main asteroid belt, but surface age analyses of each asteroid suggest these bodies are substantially younger than their putative families. Here we show, through a coupled collisional and dynamical evolution of members of these families, that neither asteroid was likely to have been created at the same time as the original family breakups, but rather are likely remnants of later disruptions of original family members, making them second, or later, generation remnants. Our model finds about 80% and 60% of asteroids currently being delivered to near-Earth orbits from the respective families of New Polana and Eulalia are second or later generation. These asteroids delivered today in the 0.5-1 km size range have median ages since their last disruption that are substantially younger than the family age, reconciling their measured crater retention ages with membership in these families.
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Affiliation(s)
- K J Walsh
- Southwest Research Institute, Boulder, CO, USA.
| | - R-L Ballouz
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD, USA
| | - W F Bottke
- Southwest Research Institute, Boulder, CO, USA
| | - C Avdellidou
- Laboratoire Lagrange, Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
- School of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK
| | - H C Connolly
- Dept. of Geology, Rowan University, Glassboro, NJ, USA
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
- American Museum of Natural History, New York, NY, USA
| | - M Delbo
- Laboratoire Lagrange, 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
| | - E R Jawin
- Smithsonian Institution National Air and Space Museum, Washington, DC, USA
| | - T McCoy
- Smithsonian Institution National Museum of Natural History, Washington, DC, USA
| | - P Michel
- Laboratoire Lagrange, Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
- University of Tokyo, Tokyo, Japan
| | - T Morota
- University of Tokyo, Tokyo, Japan
| | - M C Nolan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | - S Sugita
- University of Tokyo, Tokyo, Japan
| | - D S Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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4
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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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5
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Banik D, Gaurav K, Sharma I. Regolith flow on top-shaped asteroids. Proc Math Phys Eng Sci 2022. [DOI: 10.1098/rspa.2021.0972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We develop a continuum framework of regolith flow on asteroids. We focus on top-shaped asteroids that may be taken as consisting of regolith lying on a solid core. Depth-averaging is employed to model the regolith flow, and effects due to the asteroid’s rotation and its complex gravity field are retained. Angular momentum conservation is invoked to couple regolith flow to the asteroid’s changing shape and spin. This framework is first used to explore the equilibrium of regolith as a function of its friction, and the asteroid’s shape and spin rate. Next, we study regolith flow on top-shaped spinning asteroids and find conditions for the regolith’s shedding or deposition. We also discuss how the regolith’s flow and the asteroid’s spin influence each other. Finally, as an application, we propose and investigate the following evolution history of Bennu: a fast spinning Bennu was slowed down by multiple, impact-induced global landslides to its present spin state. Regolith was shed if the spin was higher than a critical rate. Once the spin rate fell below this critical value, regolith flow from higher latitudes began depositing regolith at its equator, giving Bennu its distinctive shape.
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Affiliation(s)
- Deepayan Banik
- Department of Aerospace Engineering, Indian Institute of Technology, Kanpur, India
- Applied Mechanics Laboratory, Department of Mechanical Engineering, Indian Institute of Technology, Kanpur, India
| | - Kumar Gaurav
- Applied Mechanics Laboratory, Department of Mechanical Engineering, Indian Institute of Technology, Kanpur, India
| | - Ishan Sharma
- Applied Mechanics Laboratory, Department of Mechanical Engineering, Indian Institute of Technology, Kanpur, India
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6
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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] [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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7
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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. NATURE GEOSCIENCE 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] [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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8
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Watanabe S, Hirabayashi M, Hirata N, Hirata N, Noguchi R, Shimaki Y, Ikeda H, Tatsumi E, Yoshikawa M, Kikuchi S, Yabuta H, Nakamura T, Tachibana S, Ishihara Y, Morota T, Kitazato K, Sakatani N, Matsumoto K, Wada K, Senshu H, Honda C, Michikami T, Takeuchi H, Kouyama T, Honda R, Kameda S, Fuse T, Miyamoto H, Komatsu G, Sugita S, Okada T, Namiki N, Arakawa M, Ishiguro M, Abe M, Gaskell R, Palmer E, Barnouin OS, Michel P, French AS, McMahon JW, Scheeres DJ, Abell PA, Yamamoto Y, Tanaka S, Shirai K, Matsuoka M, Yamada M, Yokota Y, Suzuki H, Yoshioka K, Cho Y, Tanaka S, Nishikawa N, Sugiyama T, Kikuchi H, Hemmi R, Yamaguchi T, Ogawa N, Ono G, Mimasu Y, Yoshikawa K, Takahashi T, Takei Y, Fujii A, Hirose C, Iwata T, Hayakawa M, Hosoda S, Mori O, Sawada H, Shimada T, Soldini S, Yano H, Tsukizaki R, Ozaki M, Iijima Y, Ogawa K, Fujimoto M, Ho TM, Moussi A, Jaumann R, Bibring JP, Krause C, Terui F, Saiki T, Nakazawa S, Tsuda Y. Hayabusa2 arrives at the carbonaceous asteroid 162173 Ryugu-A spinning top-shaped rubble pile. Science 2019; 364:268-272. [PMID: 30890588 DOI: 10.1126/science.aav8032] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 03/07/2019] [Indexed: 11/02/2022]
Abstract
The Hayabusa2 spacecraft arrived at the near-Earth carbonaceous asteroid 162173 Ryugu in 2018. We present Hayabusa2 observations of Ryugu's shape, mass, and geomorphology. Ryugu has an oblate "spinning top" shape, with a prominent circular equatorial ridge. Its bulk density, 1.19 ± 0.02 grams per cubic centimeter, indicates a high-porosity (>50%) interior. Large surface boulders suggest a rubble-pile structure. Surface slope analysis shows Ryugu's shape may have been produced from having once spun at twice the current rate. Coupled with the observed global material homogeneity, this suggests that Ryugu was reshaped by centrifugally induced deformation during a period of rapid rotation. From these remote-sensing investigations, we identified a suitable sample collection site on the equatorial ridge.
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Affiliation(s)
- S Watanabe
- Nagoya University, Nagoya 464-8601, Japan. .,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
| | - Na Hirata
- Kobe University, Kobe 657-8501, Japan
| | - R Noguchi
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - Y Shimaki
- 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
| | - E Tatsumi
- University of Tokyo, Tokyo 113-0033, 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
| | - S Kikuchi
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - H Yabuta
- Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - T Nakamura
- Tohoku University, Sendai 980-8578, Japan
| | - S Tachibana
- University of Tokyo, Tokyo 113-0033, Japan.,Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - Y Ishihara
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - T Morota
- Nagoya University, Nagoya 464-8601, Japan
| | - K Kitazato
- University of Aizu, Aizu-Wakamatsu 965-8580, Japan
| | - N Sakatani
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - K Matsumoto
- National Astronomical Observatory of Japan, Mitaka 181-8588, Japan.,SOKENDAI (The Graduate University for Advanced Studies), Hayama 240-0193, Japan
| | - K Wada
- Chiba Institute of Technology, Narashino 275-0016, Japan
| | - H Senshu
- Chiba Institute of Technology, Narashino 275-0016, Japan
| | - C Honda
- University of Aizu, Aizu-Wakamatsu 965-8580, Japan
| | - T Michikami
- Kindai University, Higashi-Hiroshima 739-2116, Japan
| | - H Takeuchi
- 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
| | - T Kouyama
- National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064 Japan
| | - R Honda
- Kochi University, Kochi 780-8520, Japan
| | - S Kameda
- Rikkyo University, Tokyo 171-8501, Japan
| | - T Fuse
- National Institute of Information and Communications Technology, Kashima 314-8501, Japan
| | - H Miyamoto
- University of Tokyo, Tokyo 113-0033, Japan
| | - G Komatsu
- Università d'Annunzio, 65127 Pescara, Italy.,Chiba Institute of Technology, Narashino 275-0016, Japan
| | - S Sugita
- University of Tokyo, Tokyo 113-0033, Japan
| | - T Okada
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan.,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
| | - M Arakawa
- Kobe University, Kobe 657-8501, Japan
| | - M Ishiguro
- Seoul National University, Seoul 08826, Korea
| | - 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
| | - R Gaskell
- Planetary Science Institute, Tucson, AZ 85710, USA
| | - E Palmer
- Planetary Science Institute, Tucson, AZ 85710, USA
| | - O S Barnouin
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - P Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, Centre National de la Recherche Scientifique (CNRS), Laboratoire Lagrange, 06304 Nice, France
| | - A S French
- University of Colorado, Boulder, CO 80309, USA
| | - J W McMahon
- University of Colorado, Boulder, CO 80309, USA
| | | | - P A Abell
- NASA Johnson Space Center, Houston, TX 77058, USA
| | - 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
| | - 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
| | - K Shirai
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - M Matsuoka
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - M Yamada
- Chiba Institute of Technology, Narashino 275-0016, 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
| | - H Suzuki
- Meiji University, Kawasaki 214-8571, Japan
| | - K Yoshioka
- University of Tokyo, Tokyo 113-0033, Japan
| | - Y Cho
- University of Tokyo, Tokyo 113-0033, Japan
| | - S Tanaka
- Kobe University, Kobe 657-8501, Japan
| | | | - T Sugiyama
- University of Aizu, Aizu-Wakamatsu 965-8580, Japan
| | - H Kikuchi
- University of Tokyo, Tokyo 113-0033, Japan
| | - R Hemmi
- University of Tokyo, Tokyo 113-0033, Japan
| | - T Yamaguchi
- 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
| | - 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
| | - 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
| | - 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 Hayakawa
- 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
| | - H Sawada
- 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
| | - 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
| | - Y Iijima
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - K Ogawa
- Kobe University, Kobe 657-8501, Japan
| | - M Fujimoto
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara 252-5210, Japan
| | - T-M Ho
- DLR (German Aerospace Center), Institute of Space Systems, 28359 Bremen, Germany
| | - A Moussi
- Centre National d'Etudes Spatiales (CNES), 31401 Toulouse, France
| | - R Jaumann
- DLR, Institute of Planetary Research, 12489 Berlin-Adlershof, Germany
| | - J-P Bibring
- Institute d'Astrophysique Spatiale, 91405 Orsay, France
| | - C Krause
- DLR, Microgravity User Support Center, 51147 Cologne, Germany
| | - F Terui
- 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 Nakazawa
- 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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9
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Quillen AC, Zhao Y, Chen Y, Sánchez P, Nelson RC, Schwartz SR. Impact Excitation of a Seismic Pulse and Vibrational Normal Modes on Asteroid Bennu and Associated Slumping of Regolith. ICARUS 2019; 319:312-333. [PMID: 32908320 PMCID: PMC7477816 DOI: 10.1016/j.icarus.2018.09.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We consider an impact on an asteroid that is energetic enough to cause resurfacing by seismic reverberation and just below the catastrophic disruption threshold, assuming that seismic waves are not rapidly attenuated. In asteroids with diameter less than 1 km we identify a regime where rare energetic impactors can excite seismic waves with frequencies near those of the asteroid's slowest normal modes. In this regime, the distribution of seismic reverberation is not evenly distributed across the body surface. With mass-spring model elastic simulations, we model impact excitation of seismic waves with a force pulse exerted on the surface and using three different asteroid shape models. The simulations exhibit antipodal focusing and normal mode excitation. If the impulse excited vibrational energy is long lasting, vibrations are highest at impact point, its antipode and at high surface elevations such as an equatorial ridge. A near equatorial impact launches a seismic impulse on a non-spherical body that can be focused on two additional points on an the equatorial ridge. We explore simple flow models for the morphology of vibration induced surface slumping. We find that the initial seismic pulse is unlikely to cause large shape changes. Long lasting seismic reverberation on Bennu caused by a near equatorial impact could have raised the height of its equatorial ridge by a few meters and raised two peaks on it, one near impact site and the other near its antipode.
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Affiliation(s)
- Alice C Quillen
- Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627, USA
| | - Yuhui Zhao
- Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China
| | - YuanYuan Chen
- Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China
| | - Paul Sánchez
- Colorado Center for Astrodynamics Research, The University of Colorado Boulder, UCB 431, Boulder, CO 80309-0431, United States
| | - Randal C Nelson
- Department of Computer Science, University of Rochester, Rochester, NY 14627, USA
| | - Stephen R Schwartz
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
- Laboratoire Lagrange, Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, C.S. 34229, 06304 Nice Cedex 4, France
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10
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Abstract
Asteroids are primitive Solar System bodies that evolve both collisionally and through disruptions arising from rapid rotation. These processes can lead to the formation of binary asteroids and to the release of dust, both directly and, in some cases, through uncovering frozen volatiles. In a subset of the asteroids called main-belt comets, the sublimation of excavated volatiles causes transient comet-like activity. Torques exerted by sublimation measurably influence the spin rates of active comets and might lead to the splitting of bilobate comet nuclei. The kilometre-sized main-belt asteroid 288P (300163) showed activity for several months around its perihelion 2011 (ref. 11), suspected to be sustained by the sublimation of water ice and supported by rapid rotation, while at least one component rotates slowly with a period of 16 hours (ref. 14). The object 288P is part of a young family of at least 11 asteroids that formed from a precursor about 10 kilometres in diameter during a shattering collision 7.5 million years ago. Here we report that 288P is a binary main-belt comet. It is different from the known asteroid binaries in its combination of wide separation, near-equal component size, high eccentricity and comet-like activity. The observations also provide strong support for sublimation as the driver of activity in 288P and show that sublimation torques may play an important part in binary orbit evolution.
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11
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Sesquinary catenae on the Martian satellite Phobos from reaccretion of escaping ejecta. Nat Commun 2016; 7:12591. [PMID: 27575002 PMCID: PMC5013556 DOI: 10.1038/ncomms12591] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 07/14/2016] [Indexed: 11/08/2022] Open
Abstract
The Martian satellite Phobos is criss-crossed by linear grooves and crater chains whose origin is unexplained. Anomalous grooves are relatively young, and crosscut tidally predicted stress fields as Phobos spirals towards Mars. Here we report strong correspondence between these anomalous features and reaccretion patterns of sesquinary ejecta from impacts on Phobos. Escaping ejecta persistently imprint Phobos with linear, low-velocity crater chains (catenae) that match the geometry and morphology of prominent features that do not fit the tidal model. We prove that these cannot be older than Phobos' current orbit inside Mars' Roche limit. Distinctive reimpact patterns allow sesquinary craters to be traced back to their source, for the first time across any planetary body, creating a novel way to probe planetary surface characteristics. For example, we show that catena-producing craters likely formed in the gravity regime, providing constraints on the ejecta velocity field and knowledge of source crater material properties.
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12
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First known terrestrial impact of a binary asteroid from a main belt breakup event. Sci Rep 2014; 4:6724. [PMID: 25340551 PMCID: PMC5381370 DOI: 10.1038/srep06724] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 09/25/2014] [Indexed: 11/08/2022] Open
Abstract
Approximately 470 million years ago one of the largest cosmic catastrophes occurred in our solar system since the accretion of the planets. A 200-km large asteroid was disrupted by a collision in the Main Asteroid Belt, which spawned fragments into Earth crossing orbits. This had tremendous consequences for the meteorite production and cratering rate during several millions of years following the event. The 7.5-km wide Lockne crater, central Sweden, is known to be a member of this family. We here provide evidence that Lockne and its nearby companion, the 0.7-km diameter, contemporaneous, Målingen crater, formed by the impact of a binary, presumably ‘rubble pile’ asteroid. This newly discovered crater doublet provides a unique reference for impacts by combined, and poorly consolidated projectiles, as well as for the development of binary asteroids.
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13
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Affiliation(s)
- Daniel J Scheeres
- Department of Aerospace Engineering Sciences, The University of Colorado, Boulder, Colorado 80309, USA
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14
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Jacobson SA, Marzari F, Rossi A, Scheeres DJ, Davis DR. Effect of rotational disruption on the size–frequency distribution of the Main Belt asteroid population. ACTA ACUST UNITED AC 2014. [DOI: 10.1093/mnrasl/slu006] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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15
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Abstract
Large meteors (or superbolides [Ceplecha Z, et al. (1999) Meteoroids 1998:37-54]), although rare in recorded history, give sobering testimony to civilization's inherent vulnerability. A not-so-subtle reminder came on the morning of February 15, 2013, when a large meteoroid hurtled into the Earth's atmosphere, forming a superbolide near the city of Chelyabinsnk, Russia, ∼1,500 km east of Moscow, Russia [Ivanova MA, et al. (2013) Abstracts of the 76th Annual Meeting of the Meteoritical Society, 5366]. The object exploded in the stratosphere, and the ensuing shock wave blasted the city of Chelyabinsk, damaging structures and injuring hundreds. Details of trajectory are important for determining its specific source, the likelihood of future events, and potential mitigation measures. Earth-viewing environmental satellites can assist in these assessments. Here we examine satellite observations of the Chelyabinsk superbolide debris trail, collected within minutes of its entry. Estimates of trajectory are derived from differential views of the significantly parallax-displaced [e.g., Hasler AF (1981) Bull Am Meteor Soc 52:194-212] debris trail. The 282.7 ± 2.3° azimuth of trajectory, 18.5 ± 3.8° slope to the horizontal, and 17.7 ± 0.5 km/s velocity derived from these satellites agree well with parameters inferred from the wealth of surface-based photographs and amateur videos. More importantly, the results demonstrate the general ability of Earth-viewing satellites to provide valuable insight on trajectory reconstruction in the more likely scenario of sparse or nonexistent surface observations.
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16
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Ruiz-Suárez JC. Penetration of projectiles into granular targets. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2013; 76:066601. [PMID: 23660625 DOI: 10.1088/0034-4885/76/6/066601] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Energetic collisions of subatomic particles with fixed or moving targets have been very valuable to penetrate into the mysteries of nature. But the mysteries are quite intriguing when projectiles and targets are macroscopically immense. We know that countless debris wandering in space impacted (and still do) large asteroids, moons and planets; and that millions of craters on their surfaces are traces of such collisions. By classifying and studying the morphology of such craters, geologists and astrophysicists obtain important clues to understand the origin and evolution of the Solar System. This review surveys knowledge about crater phenomena in the planetary science context, avoiding detailed descriptions already found in excellent papers on the subject. Then, it examines the most important results reported in the literature related to impact and penetration phenomena in granular targets obtained by doing simple experiments. The main goal is to discern whether both schools, one that takes into account the right ingredients (planetary bodies and very high energies) but cannot physically reproduce the collisions, and the other that easily carries out the collisions but uses laboratory ingredients (small projectiles and low energies), can arrive at a synergistic intersection point.
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17
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Formation of asteroid pairs by rotational fission. Nature 2010; 466:1085-8. [DOI: 10.1038/nature09315] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 06/22/2010] [Indexed: 11/08/2022]
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18
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Keller HU, Barbieri C, Koschny D, Lamy P, Rickman H, Rodrigo R, Sierks H, A’Hearn MF, Angrilli F, Barucci MA, Bertaux JL, Cremonese G, Da Deppo V, Davidsson B, De Cecco M, Debei S, Fornasier S, Fulle M, Groussin O, Gutierrez PJ, Hviid SF, Ip WH, Jorda L, Knollenberg J, Kramm JR, Kührt E, Küppers M, Lara LM, Lazzarin M, Moreno JL, Marzari F, Michalik H, Naletto G, Sabau L, Thomas N, Wenzel KP, Bertini I, Besse S, Ferri F, Kaasalainen M, Lowry S, Marchi S, Mottola S, Sabolo W, Schröder SE, Spjuth S, Vernazza P. E-Type Asteroid (2867) Steins as Imaged by OSIRIS on Board Rosetta. Science 2010; 327:190-3. [DOI: 10.1126/science.1179559] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- H. U. Keller
- Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
| | | | - D. Koschny
- European Space and Technology Centre, Noordwijk, Netherlands
| | - P. Lamy
- Laboratoire d'Astrophysique de Marseille, Université de Provence, Marseille, France
| | - H. Rickman
- Institute för Astronomi och Rymdfysik, Uppsala, Sweden
- Polish Academy of Sciences Space Research Center, Warsaw, Poland
| | - R. Rodrigo
- Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - H. Sierks
- Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
| | | | | | | | - J.-L. Bertaux
- Services d’Aéronomie de CNRS, Verrières le Buisson, France
| | | | - V. Da Deppo
- Consiglio Nazionale delle Ricerche-Istituto Nazionale per la Fisica della Materia, Luxor, Padova, Italy
| | - B. Davidsson
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | | | - S. Debei
- University of Padova, Padova, Italy
| | | | - M. Fulle
- International School for Advanced Studies, Trieste, Italy
| | - O. Groussin
- Laboratoire d'Astrophysique de Marseille, Université de Provence, Marseille, France
| | - P. J. Gutierrez
- Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - S. F. Hviid
- Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
| | - W.-H. Ip
- National Central University, Jhongli City, Taiwan
| | - L. Jorda
- Laboratoire d'Astrophysique de Marseille, Université de Provence, Marseille, France
| | | | - J. R. Kramm
- Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
| | - E. Kührt
- German Aerospace Center, Berlin, Germany
| | - M. Küppers
- European Space Astronomy Centre (ESAC), Madrid, Spain
| | - L.-M. Lara
- Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas, Granada, Spain
| | | | - J. Lopez Moreno
- Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas, Granada, Spain
| | | | - H. Michalik
- Institute of Computer and Network Engineering, Braunschweig, Germany
| | | | - L. Sabau
- Instituto Nacional de Técnica Aérospacial, Torrejon de Ardoz, Spain
| | - N. Thomas
- Physikalisches Institut der Universität Bern, Switzerland
| | - K.-P. Wenzel
- European Space and Technology Centre, Noordwijk, Netherlands
| | - I. Bertini
- Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - S. Besse
- Laboratoire d'Astrophysique de Marseille, Université de Provence, Marseille, France
| | - F. Ferri
- University of Padova, Padova, Italy
| | | | - S. Lowry
- University of Kent, Canterbury, UK
| | | | - S. Mottola
- German Aerospace Center, Berlin, Germany
| | - W. Sabolo
- Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - S. E. Schröder
- Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
| | - S. Spjuth
- Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
| | - P. Vernazza
- European Space and Technology Centre, Noordwijk, Netherlands
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