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Zhang C, Leyva V, Wang J, Turner AM, Mcanally M, Herath A, Meinert C, Young LA, Kaiser RI. Ionizing radiation exposure on Arrokoth shapes a sugar world. Proc Natl Acad Sci U S A 2024; 121:e2320215121. [PMID: 38830103 PMCID: PMC11181085 DOI: 10.1073/pnas.2320215121] [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: 11/17/2023] [Accepted: 04/18/2024] [Indexed: 06/05/2024] Open
Abstract
The Kuiper Belt object (KBO) Arrokoth, the farthest object in the Solar System ever visited by a spacecraft, possesses a distinctive reddish surface and is characterized by pronounced spectroscopic features associated with methanol. However, the fundamental processes by which methanol ices are converted into reddish, complex organic molecules on Arrokoth's surface have remained elusive. Here, we combine laboratory simulation experiments with a spectroscopic characterization of methanol ices exposed to proxies of galactic cosmic rays (GCRs). Our findings reveal that the surface exposure of methanol ices at 40 K can replicate the color slopes of Arrokoth. Sugars and their derivatives (acids, alcohols) with up to six carbon atoms, including glucose and ribose-fundamental building block of RNA-were ubiquitously identified. In addition, polycyclic aromatic hydrocarbons (PAHs) with up to six ring units (13C22H12) were also observed. These sugars and their derivatives along with PAHs connected by unsaturated linkers represent key molecules rationalizing the reddish appearance of Arrokoth. The formation of abundant sugar-related molecules dubs Arrokoth as a sugar world and provides a plausible abiotic preparation route for a key class of biorelevant molecules on the surface of KBOs prior to their delivery to prebiotic Earth.
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Affiliation(s)
- Chaojiang Zhang
- Department of Chemistry, University of Hawaii at Mānoa, Honolulu, HI96822
- W.M. Keck Laboratory in Astrochemistry, University of Hawaii at Mānoa, Honolulu, HI96822
| | - Vanessa Leyva
- Université Côte d’Azur, Institut de Chimie de Nice, UMR 7272 CNRS, 06108Nice, France
| | - Jia Wang
- Department of Chemistry, University of Hawaii at Mānoa, Honolulu, HI96822
- W.M. Keck Laboratory in Astrochemistry, University of Hawaii at Mānoa, Honolulu, HI96822
| | - Andrew M. Turner
- Department of Chemistry, University of Hawaii at Mānoa, Honolulu, HI96822
- W.M. Keck Laboratory in Astrochemistry, University of Hawaii at Mānoa, Honolulu, HI96822
| | - Mason Mcanally
- Department of Chemistry, University of Hawaii at Mānoa, Honolulu, HI96822
- W.M. Keck Laboratory in Astrochemistry, University of Hawaii at Mānoa, Honolulu, HI96822
| | - Ashanie Herath
- Department of Chemistry, University of Hawaii at Mānoa, Honolulu, HI96822
- W.M. Keck Laboratory in Astrochemistry, University of Hawaii at Mānoa, Honolulu, HI96822
| | - Cornelia Meinert
- Université Côte d’Azur, Institut de Chimie de Nice, UMR 7272 CNRS, 06108Nice, France
| | - Leslie A. Young
- Department of Space Studies, Southwest Research Institute, Boulder, CO80302
| | - Ralf I. Kaiser
- Department of Chemistry, University of Hawaii at Mānoa, Honolulu, HI96822
- W.M. Keck Laboratory in Astrochemistry, University of Hawaii at Mānoa, Honolulu, HI96822
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2
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Howard CM, Wood IG, Knight KS, Fortes AD. Ab initio simulations of α- and β-ammonium carbamate (NH 4·NH 2CO 2), and the thermal expansivity of deuterated α-ammonium carbamate from 4.2 to 180 K by neutron powder diffraction. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2022; 78:459-475. [PMID: 35702963 PMCID: PMC9254591 DOI: 10.1107/s2052520622002645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/08/2022] [Indexed: 06/15/2023]
Abstract
Experimental and computational studies of ammonium carbamate have been carried out, with the objective of studying the elastic anisotropy of the framework manifested in (i) the thermal expansion and (ii) the compressibility; furthermore, the relative thermodynamic stability of the two known polymorphs has been evaluated computationally. Using high-resolution neutron powder diffraction data, the crystal structure of α-ammonium carbamate (ND4·ND2CO2) has been refined [space group Pbca, Z = 8, with a = 17.05189 (15), b = 6.43531 (7), c = 6.68093 (7) Å and V = 733.126 (9) Å3 at 4.2 K] and the thermal expansivity of α-ammonium carbamate has been measured over the temperature range 4.2-180 K. The expansivity shows a high degree of anisotropy, with the b axis most expandable. The ab initio computational studies were carried out on the α- and β-polymorphs of ammonium carbamate using density functional theory. Fitting equations of state to the P(V) points of the simulations (run athermally) gave the following values: V0 = 744 (2) Å3 and bulk modulus K0 = 16.5 (4) GPa for the α-polymorph, and V0 = 713.6 (5) Å3 and K0 = 24.4 (4) GPa for the β-polymorph. The simulations show good agreement with the thermoelastic behaviour of α-ammonium carbamate. Both phases show a high-degree of anisotropy; in particular, α-ammonium carbamate shows unusual compressive behaviour, being determined to have negative linear compressibility (NLC) along its a axis above 5 GPa. The thermodynamically stable phase at ambient pressure is the α-polymorph, with a calculated enthalpy difference with respect to the β-polymorph of 0.399 kJ mol-1; a transition to the β-polymorph could occur at ∼0.4 GPa.
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Affiliation(s)
- Christopher M. Howard
- Bayerisches Geoinstitut (BGI), University of Bayreuth, 95447 Bayreuth, Germany
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Ian G. Wood
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Kevin S. Knight
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - A. Dominic Fortes
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
- ISIS Facility, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
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3
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Organic Components of Small Bodies in the Outer Solar System: Some Results of the New Horizons Mission. Life (Basel) 2020; 10:life10080126. [PMID: 32731390 PMCID: PMC7460487 DOI: 10.3390/life10080126] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/18/2020] [Accepted: 07/24/2020] [Indexed: 11/21/2022] Open
Abstract
The close encounters of the Pluto–Charon system and the Kuiper Belt object Arrokoth (formerly 2014 MU69) by NASA’s New Horizons spacecraft in 2015 and 2019, respectively, have given new perspectives on the most distant planetary bodies yet explored. These bodies are key indicators of the composition, chemistry, and dynamics of the outer regions of the Solar System’s nascent environment. Pluto and Charon reveal characteristics of the largest Kuiper Belt objects formed in the dynamically evolving solar nebula inward of ~30 AU, while the much smaller Arrokoth is a largely undisturbed relic of accretion at ~45 AU. The surfaces of Pluto and Charon are covered with volatile and refractory ices and organic components, and have been shaped by geological activity. On Pluto, N2, CO and CH4 are exchanged between the atmosphere and surface as gaseous and condensed phases on diurnal, seasonal and longer timescales, while Charon’s surface is primarily inert H2O ice with an ammoniated component and a polar region colored with a macromolecular organic deposit. Arrokoth is revealed as a fused binary body in a relatively benign space environment where it originated and has remained for the age of the Solar System. Its surface is a mix of CH3OH ice, a red-orange pigment of presumed complex organic material, and possibly other undetected components.
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4
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The wide-binary origin of (2014) MU 69-like Kuiper belt contact binaries. Nature 2020; 580:463-466. [PMID: 32322077 DOI: 10.1038/s41586-020-2194-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 02/27/2020] [Indexed: 11/08/2022]
Abstract
Following its flyby and first imaging of the Pluto-Charon binary, the New Horizons spacecraft visited the Kuiper belt object (KBO) 2014 MU69 (also known as (486958) Arrokoth). The imaging showed MU69 to be a contact binary that rotates at a low spin period (15.92 hours), is made of two individual lobes connected by a narrow neck and has a high obliquity (about 98 degrees)1, properties that are similar to those of other KBO contact binaries inferred through photometric observations2. However, all scenarios suggested so far for the origins of such configurations3-5 have failed to reproduce these properties and their probable frequent occurrence in the Kuiper belt. Here we show that semi-secular perturbations6,7 operating on only ultrawide KBO binaries close to their stability limit can robustly lead to gentle, slow binary mergers at arbitrarily high obliquities but low rotational velocities, reproducing the characteristics of MU69 and other similar oblique contact binaries. Using N-body simulations, we find that approximately 15 per cent of all ultrawide binaries with a cosine-uniform inclination distribution5,9 are likely to merge through this process. Moreover, we find that such mergers are sufficiently gentle to deform the shape of the KBO only slightly. The semi-secular contact binary formation channel not only explains the observed properties of MU69, but may also apply to other Kuiper belt or asteroid belt binaries and in the Solar System and extra-solar moon systems.
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5
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Sandford SA, Nuevo M, Bera PP, Lee TJ. Prebiotic Astrochemistry and the Formation of Molecules of Astrobiological Interest in Interstellar Clouds and Protostellar Disks. Chem Rev 2020; 120:4616-4659. [DOI: 10.1021/acs.chemrev.9b00560] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Scott A. Sandford
- NASA Ames Research Center, MS 245-6, Moffett Field, California 94035, United States
| | - Michel Nuevo
- NASA Ames Research Center, MS 245-6, Moffett Field, California 94035, United States
- BAER Institute, NASA Research Park, MS 18-4, Moffett Field, California 94035, United States
| | - Partha P. Bera
- NASA Ames Research Center, MS 245-6, Moffett Field, California 94035, United States
- BAER Institute, NASA Research Park, MS 18-4, Moffett Field, California 94035, United States
| | - Timothy J. Lee
- NASA Ames Research Center, MS 245-3, Moffett Field, California 94035, United States
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6
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Rocha WRM, Pilling S, Domaracka A, Rothard H, Boduch P. Infrared complex refractive index of N-containing astrophysical ices free of water processed by cosmic-ray simulated in laboratory. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 228:117826. [PMID: 31784228 DOI: 10.1016/j.saa.2019.117826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/18/2019] [Accepted: 11/18/2019] [Indexed: 06/10/2023]
Abstract
Several nitrogen-containing molecules have been unambiguously identified in the Solar System and in the Interstellar Medium. It is believed that such a rich inventory of species is a result of the energetic processing of astrophysical ices during the interaction with ionizing radiation. An intrinsic parameter of matter, the complex refractive index, stores all the "chemical memory" triggered by energetic processing, and therefore might be used to probe ice observations in the infrared. In this study, four N-containing ices have been condensed in an ultra-high vacuum chamber and processed by heavy ions (O and Ni) with energies between 0.2 and 15.7 MeV at the Grand Accélérateur National d'Ions Lourds (GANIL), in Caen, France. All chemical changes were monitored in situ by Infrared Absorption Spectroscopy. The complex refractive index was calculated directly from the absorbance spectrum, by using the Lambert-Beer and Kramers-Kroning relations, and the values are available in an online database: https://www1.univap.br/gaa/nkabs-database/data.htm. As a result, other than the database, it was observed that non-polar ices are more destroyed by sputtering than polar ones. Such destruction and chemical evolution lead to variation in the IR albedo of samples addressed in this paper.
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Affiliation(s)
- W R M Rocha
- Niels Bohr Institute & Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5-7, Copenhagen K. DK-1350, Denmark; Universidade do Vale do Paraíba (UNIVAP), Laboratório de Astroquímica e Astrobiologia (LASA), Av. Shishima Hifumi, 2911, Urbanova, São José dos Campos, CEP: 12244000, SP, Brazil.
| | - S Pilling
- Universidade do Vale do Paraíba (UNIVAP), Laboratório de Astroquímica e Astrobiologia (LASA), Av. Shishima Hifumi, 2911, Urbanova, São José dos Campos, CEP: 12244000, SP, Brazil; Departamento de Física, Instituto Tecnólogico de Aeronáutica, ITA - DCTA, Vila das Acácias, São José dos Campos 12228-900 , SP, Brazil
| | - A Domaracka
- Centre de Recherche sur les Ions, les Matériaux et la Photonique, Normandie Univ, ENSICAEN, UNICAEN, CEA, CNRS, CIMAP, Caen 14000, France
| | - H Rothard
- Centre de Recherche sur les Ions, les Matériaux et la Photonique, Normandie Univ, ENSICAEN, UNICAEN, CEA, CNRS, CIMAP, Caen 14000, France
| | - P Boduch
- Centre de Recherche sur les Ions, les Matériaux et la Photonique, Normandie Univ, ENSICAEN, UNICAEN, CEA, CNRS, CIMAP, Caen 14000, France
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7
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Spencer JR, Stern SA, Moore JM, Weaver HA, Singer KN, Olkin CB, Verbiscer AJ, McKinnon WB, Parker JW, Beyer RA, Keane JT, Lauer TR, Porter SB, White OL, Buratti BJ, El-Maarry MR, Lisse CM, Parker AH, Throop HB, Robbins SJ, Umurhan OM, Binzel RP, Britt DT, Buie MW, Cheng AF, Cruikshank DP, Elliott HA, Gladstone GR, Grundy WM, Hill ME, Horanyi M, Jennings DE, Kavelaars JJ, Linscott IR, McComas DJ, McNutt RL, Protopapa S, Reuter DC, Schenk PM, Showalter MR, Young LA, Zangari AM, Abedin AY, Beddingfield CB, Benecchi SD, Bernardoni E, Bierson CJ, Borncamp D, Bray VJ, Chaikin AL, Dhingra RD, Fuentes C, Fuse T, Gay PL, Gwyn SDJ, Hamilton DP, Hofgartner JD, Holman MJ, Howard AD, Howett CJA, Karoji H, Kaufmann DE, Kinczyk M, May BH, Mountain M, Pätzold M, Petit JM, Piquette MR, Reid IN, Reitsema HJ, Runyon KD, Sheppard SS, Stansberry JA, Stryk T, Tanga P, Tholen DJ, Trilling DE, Wasserman LH. The geology and geophysics of Kuiper Belt object (486958) Arrokoth. Science 2020; 367:science.aay3999. [PMID: 32054694 DOI: 10.1126/science.aay3999] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 01/27/2020] [Indexed: 11/02/2022]
Abstract
The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, is composed of primitive objects preserving information about Solar System formation. In January 2019, the New Horizons spacecraft flew past one of these objects, the 36-kilometer-long contact binary (486958) Arrokoth (provisional designation 2014 MU69). Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters in diameter) within a radius of 8000 kilometers. Arrokoth has a lightly cratered, smooth surface with complex geological features, unlike those on previously visited Solar System bodies. The density of impact craters indicates the surface dates from the formation of the Solar System. The two lobes of the contact binary have closely aligned poles and equators, constraining their accretion mechanism.
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Affiliation(s)
- J R Spencer
- Southwest Research Institute, Boulder, CO 80302, USA.
| | - S A Stern
- Southwest Research Institute, Boulder, CO 80302, USA
| | - J M Moore
- NASA Ames Research Center, Moffett Field, CA 94035-1000, USA
| | - H A Weaver
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - K N Singer
- Southwest Research Institute, Boulder, CO 80302, USA
| | - C B Olkin
- Southwest Research Institute, Boulder, CO 80302, USA
| | - A J Verbiscer
- Department of Astronomy, University of Virginia, Charlottesville, VA 22904, USA
| | - W B McKinnon
- Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University, St. Louis, MO 63130, USA
| | - J Wm Parker
- Southwest Research Institute, Boulder, CO 80302, USA
| | - R A Beyer
- SETI Institute, Mountain View, CA 94043, USA.,NASA Ames Research Center, Moffett Field, CA 94035-1000, USA
| | - J T Keane
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - T R Lauer
- National Science Foundation's National Optical Infrared Astronomy Research Laboratory, Tucson, AZ 26732, USA
| | - S B Porter
- Southwest Research Institute, Boulder, CO 80302, USA
| | - O L White
- SETI Institute, Mountain View, CA 94043, USA.,NASA Ames Research Center, Moffett Field, CA 94035-1000, USA
| | - B J Buratti
- Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA 91109, USA
| | - M R El-Maarry
- Department of Earth and Planetary Sciences, Birkbeck, University of London, London WC1E 7HX, UK.,University College London, Gower St, Bloomsbury, London WC1E 6BT, UK
| | - C M Lisse
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - A H Parker
- Southwest Research Institute, Boulder, CO 80302, USA
| | - H B Throop
- Independent Consultant, Washington, D.C., USA
| | - S J Robbins
- Southwest Research Institute, Boulder, CO 80302, USA
| | - O M Umurhan
- NASA Ames Research Center, Moffett Field, CA 94035-1000, USA
| | - R P Binzel
- Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - D T Britt
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA
| | - M W Buie
- Southwest Research Institute, Boulder, CO 80302, USA
| | - A F Cheng
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - D P Cruikshank
- NASA Ames Research Center, Moffett Field, CA 94035-1000, USA
| | - H A Elliott
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - G R Gladstone
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - W M Grundy
- Lowell Observatory, Flagstaff, AZ 86001, USA.,Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - M E Hill
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - M Horanyi
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA
| | - D E Jennings
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - J J Kavelaars
- National Research Council of Canada, Victoria, BC V9E 2E7, Canada
| | - I R Linscott
- Independent Consultant, Mountain View, CA 94043, USA
| | - D J McComas
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | - R L McNutt
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - S Protopapa
- Southwest Research Institute, Boulder, CO 80302, USA
| | - D C Reuter
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - P M Schenk
- Lunar and Planetary Institute, Houston, TX 77058, USA
| | | | - L A Young
- Southwest Research Institute, Boulder, CO 80302, USA
| | - A M Zangari
- Southwest Research Institute, Boulder, CO 80302, USA
| | - A Y Abedin
- National Research Council of Canada, Victoria, BC V9E 2E7, Canada
| | | | - S D Benecchi
- Planetary Science Institute, Tucson, AZ 85719, USA
| | - E Bernardoni
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA
| | - C J Bierson
- Earth and Planetary Science Department, University of California, Santa Cruz, CA 95064, USA
| | - D Borncamp
- Decipher Technology Studios, Alexandria, VA 22314, USA
| | - V J Bray
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA
| | - A L Chaikin
- Independent Science Writer, Arlington, VT 05250, USA
| | | | - C Fuentes
- Universidad de Chile, Centro de Astrofísica y Tecnologías Afines, Santiago, Chile
| | - T Fuse
- Kashima Space Technology Center, National Institute of Information and Communications Technology, Kashima, Ibaraki 314-8501, Japan
| | - P L Gay
- Planetary Science Institute, Tucson, AZ 85719, USA
| | - S D J Gwyn
- National Research Council of Canada, Victoria, BC V9E 2E7, Canada
| | - D P Hamilton
- Department of Astronomy, University of Maryland, College Park, MD 20742, USA
| | - J D Hofgartner
- Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA 91109, USA
| | - M J Holman
- Center for Astrophysics, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA
| | - A D Howard
- Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22904, USA
| | - C J A Howett
- Southwest Research Institute, Boulder, CO 80302, USA
| | - H Karoji
- National Institutes of Natural Sciences, Tokyo, Japan
| | - D E Kaufmann
- Southwest Research Institute, Boulder, CO 80302, USA
| | - M Kinczyk
- Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - B H May
- Independent Collaborator, Windlesham GU20 6YW, UK
| | - M Mountain
- Association of Universities for Research in Astronomy, Washington, DC 20004, USA
| | - M Pätzold
- Rheinisches Institut für Umweltforschung an der Universität zu Köln, Cologne 50931, Germany
| | - J M Petit
- Institut Univers, Temps-fréquence, Interfaces, Nanostructures, Atmosphère et environnement, Molécules, Unité Mixte de Recherche, Centre National de la Recherche Scientifique, Universite Bourgogne Franche Comte, F-25000 Besancon, France
| | - M R Piquette
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA
| | - I N Reid
- Space Telescope Science Institute, Baltimore, MD 21218, USA
| | | | - K D Runyon
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - S S Sheppard
- Department of Terrestrial Magnetism, Carnegie Institution for Science, Washington, DC 20015, USA
| | - J A Stansberry
- Space Telescope Science Institute, Baltimore, MD 21218, USA
| | - T Stryk
- Roane State Community College, Oak Ridge, TN 37830, USA
| | - P Tanga
- Université Côte d'Azur, Observatoire de la Côte d'Azur, Laboratoire Lagrange/ Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7293, 06304 Nice Cedex 4, France
| | - D J Tholen
- Institute for Astronomy, University of Hawaii, Honolulu, HI 96822, USA
| | - D E Trilling
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, 86011, USA
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8
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Grundy WM, Bird MK, Britt DT, Cook JC, Cruikshank DP, Howett CJA, Krijt S, Linscott IR, Olkin CB, Parker AH, Protopapa S, Ruaud M, Umurhan OM, Young LA, Dalle Ore CM, Kavelaars JJ, Keane JT, Pendleton YJ, Porter SB, Scipioni F, Spencer JR, Stern SA, Verbiscer AJ, Weaver HA, Binzel RP, Buie MW, Buratti BJ, Cheng A, Earle AM, Elliott HA, Gabasova L, Gladstone GR, Hill ME, Horanyi M, Jennings DE, Lunsford AW, McComas DJ, McKinnon WB, McNutt RL, Moore JM, Parker JW, Quirico E, Reuter DC, Schenk PM, Schmitt B, Showalter MR, Singer KN, Weigle GE, Zangari AM. Color, composition, and thermal environment of Kuiper Belt object (486958) Arrokoth. Science 2020; 367:science.aay3705. [PMID: 32054693 DOI: 10.1126/science.aay3705] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 01/22/2020] [Indexed: 11/02/2022]
Abstract
The outer Solar System object (486958) Arrokoth (provisional designation 2014 MU69) has been largely undisturbed since its formation. We studied its surface composition using data collected by the New Horizons spacecraft. Methanol ice is present along with organic material, which may have formed through irradiation of simple molecules. Water ice was not detected. This composition indicates hydrogenation of carbon monoxide-rich ice and/or energetic processing of methane condensed on water ice grains in the cold, outer edge of the early Solar System. There are only small regional variations in color and spectra across the surface, which suggests that Arrokoth formed from a homogeneous or well-mixed reservoir of solids. Microwave thermal emission from the winter night side is consistent with a mean brightness temperature of 29 ± 5 kelvin.
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Affiliation(s)
- W M Grundy
- Lowell Observatory, Flagstaff, AZ 86001, USA. .,Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - M K Bird
- Argelander-Institut für Astronomie, University of Bonn, D-53121 Bonn, Germany.,Rheinisches Institut für Umweltforschung, Universität zu Köln, 50931 Cologne, Germany
| | - D T Britt
- University of Central Florida, Orlando, FL 32816, USA
| | - J C Cook
- Pinhead Institute, Telluride, CO 81435, USA
| | | | - C J A Howett
- Southwest Research Institute, Boulder, CO 80302, USA
| | - S Krijt
- Steward Observatory, University of Arizona, Tucson, AZ 85719, USA
| | | | - C B Olkin
- Southwest Research Institute, Boulder, CO 80302, USA
| | - A H Parker
- Southwest Research Institute, Boulder, CO 80302, USA
| | - S Protopapa
- Southwest Research Institute, Boulder, CO 80302, USA
| | - M Ruaud
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - O M Umurhan
- NASA Ames Research Center, Moffett Field, CA 94035, USA.,Carl Sagan Center, SETI Institute, Mountain View, CA 94043, USA
| | - L A Young
- Southwest Research Institute, Boulder, CO 80302, USA
| | - C M Dalle Ore
- NASA Ames Research Center, Moffett Field, CA 94035, USA.,Carl Sagan Center, SETI Institute, Mountain View, CA 94043, USA
| | - J J Kavelaars
- National Research Council, Victoria, BC V9E 2E7, Canada.,Department of Physics and Astronomy, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - J T Keane
- California Institute of Technology, Pasadena, CA 91125, USA
| | - Y J Pendleton
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - S B Porter
- Southwest Research Institute, Boulder, CO 80302, USA
| | - F Scipioni
- NASA Ames Research Center, Moffett Field, CA 94035, USA.,Carl Sagan Center, SETI Institute, Mountain View, CA 94043, USA
| | - J R Spencer
- Southwest Research Institute, Boulder, CO 80302, USA
| | - S A Stern
- Southwest Research Institute, Boulder, CO 80302, USA
| | - A J Verbiscer
- University of Virginia, Charlottesville, VA 22904, USA
| | - H A Weaver
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - R P Binzel
- Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - M W Buie
- Southwest Research Institute, Boulder, CO 80302, USA
| | - B J Buratti
- NASA Jet Propulsion Laboratory, La Cañada Flintridge, CA 91011, USA
| | - A Cheng
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - A M Earle
- Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - H A Elliott
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - L Gabasova
- Institut de Planétologie et d'Astrophysique de Grenoble, Centre National de la Recherche Scientifique, Université Grenoble Alpes, Grenoble, France
| | - G R Gladstone
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - M E Hill
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - M Horanyi
- University of Colorado, Boulder, CO 80309, USA
| | - D E Jennings
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - A W Lunsford
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - D J McComas
- Princeton University, Princeton, NJ 08544, USA
| | | | - R L McNutt
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - J M Moore
- NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - J W Parker
- Southwest Research Institute, Boulder, CO 80302, USA
| | - E Quirico
- Institut de Planétologie et d'Astrophysique de Grenoble, Centre National de la Recherche Scientifique, Université Grenoble Alpes, Grenoble, France
| | - D C Reuter
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - P M Schenk
- Lunar and Planetary Institute, Houston, TX 77058, USA
| | - B Schmitt
- Institut de Planétologie et d'Astrophysique de Grenoble, Centre National de la Recherche Scientifique, Université Grenoble Alpes, Grenoble, France
| | - M R Showalter
- Carl Sagan Center, SETI Institute, Mountain View, CA 94043, USA
| | - K N Singer
- Southwest Research Institute, Boulder, CO 80302, USA
| | - G E Weigle
- Big Head Endian LLC, Leawood, KS 67019, USA
| | - A M Zangari
- Southwest Research Institute, Boulder, CO 80302, USA
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9
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McKinnon WB, Richardson DC, Marohnic JC, Keane JT, Grundy WM, Hamilton DP, Nesvorný D, Umurhan OM, Lauer TR, Singer KN, Stern SA, Weaver HA, Spencer JR, Buie MW, Moore JM, Kavelaars JJ, Lisse CM, Mao X, Parker AH, Porter SB, Showalter MR, Olkin CB, Cruikshank DP, Elliott HA, Gladstone GR, Parker JW, Verbiscer AJ, Young LA. The solar nebula origin of (486958) Arrokoth, a primordial contact binary in the Kuiper Belt. Science 2020; 367:science.aay6620. [PMID: 32054695 DOI: 10.1126/science.aay6620] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 01/27/2020] [Indexed: 11/02/2022]
Abstract
The New Horizons spacecraft's encounter with the cold classical Kuiper Belt object (486958) Arrokoth (provisional designation 2014 MU69) revealed a contact-binary planetesimal. We investigated how Arrokoth formed and found that it is the product of a gentle, low-speed merger in the early Solar System. Its two lenticular lobes suggest low-velocity accumulation of numerous smaller planetesimals within a gravitationally collapsing cloud of solid particles. The geometric alignment of the lobes indicates that they were a co-orbiting binary that experienced angular momentum loss and subsequent merger, possibly because of dynamical friction and collisions within the cloud or later gas drag. Arrokoth's contact-binary shape was preserved by the benign dynamical and collisional environment of the cold classical Kuiper Belt and therefore informs the accretion processes that operated in the early Solar System.
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Affiliation(s)
- W B McKinnon
- Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, St. Louis, MO 63130, USA.
| | - D C Richardson
- Department of Astronomy, University of Maryland, College Park, MD 20742, USA
| | - J C Marohnic
- Department of Astronomy, University of Maryland, College Park, MD 20742, USA
| | - J T Keane
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - W M Grundy
- Lowell Observatory, Flagstaff, AZ 86001, USA.,Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - D P Hamilton
- Department of Astronomy, University of Maryland, College Park, MD 20742, USA
| | - D Nesvorný
- Division of Space Science and Engineering, Southwest Research Institute, Boulder, CO 80302, USA
| | - O M Umurhan
- NASA Ames Research Center, Space Science Division, Moffett Field, CA 94035, USA.,SETI Institute, Mountain View, CA 94043, USA
| | - T R Lauer
- National Optical-Infrared Astronomy Research Laboratory, National Science Foundation, Tucson, AZ 85726, USA
| | - K N Singer
- Division of Space Science and Engineering, Southwest Research Institute, Boulder, CO 80302, USA
| | - S A Stern
- Division of Space Science and Engineering, Southwest Research Institute, Boulder, CO 80302, USA
| | - H A Weaver
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - J R Spencer
- National Research Council of Canada, Victoria, BC V9E 2E7, Canada
| | - M W Buie
- Division of Space Science and Engineering, Southwest Research Institute, Boulder, CO 80302, USA
| | - J M Moore
- NASA Ames Research Center, Space Science Division, Moffett Field, CA 94035, USA
| | - J J Kavelaars
- National Research Council of Canada, Victoria, BC V9E 2E7, Canada
| | - C M Lisse
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - X Mao
- Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - A H Parker
- Division of Space Science and Engineering, Southwest Research Institute, Boulder, CO 80302, USA
| | - S B Porter
- Division of Space Science and Engineering, Southwest Research Institute, Boulder, CO 80302, USA
| | | | - C B Olkin
- Division of Space Science and Engineering, Southwest Research Institute, Boulder, CO 80302, USA
| | - D P Cruikshank
- NASA Ames Research Center, Space Science Division, Moffett Field, CA 94035, USA
| | - H A Elliott
- Division of Space Science and Engineering, Southwest Research Institute, San Antonio, TX 78238, USA.,Department of Physics and Astronomy, University of Texas, San Antonio, TX 78249, USA
| | - G R Gladstone
- Division of Space Science and Engineering, Southwest Research Institute, San Antonio, TX 78238, USA
| | - J Wm Parker
- Division of Space Science and Engineering, Southwest Research Institute, Boulder, CO 80302, USA
| | - A J Verbiscer
- Department of Astronomy, University of Virginia, Charlottesville, VA 22904, USA
| | - L A Young
- Division of Space Science and Engineering, Southwest Research Institute, Boulder, CO 80302, USA
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10
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“Celestial snowman” starts to reveal its secrets. Proc Natl Acad Sci U S A 2019; 116:18749-18752. [DOI: 10.1073/pnas.1913629116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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