1
|
Styczinski MJ, Cooper ZS, Glaser DM, Lehmer O, Mierzejewski V, Tarnas J. Chapter 7: Assessing Habitability Beyond Earth. ASTROBIOLOGY 2024; 24:S143-S163. [PMID: 38498826 DOI: 10.1089/ast.2021.0097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
All known life on Earth inhabits environments that maintain conditions between certain extremes of temperature, chemical composition, energy availability, and so on (Chapter 6). Life may have emerged in similar environments elsewhere in the Solar System and beyond. The ongoing search for life elsewhere mainly focuses on those environments most likely to support life, now or in the past-that is, potentially habitable environments. Discussion of habitability is necessarily based on what we know about life on Earth, as it is our only example. This chapter gives an overview of the known and presumed requirements for life on Earth and discusses how these requirements can be used to assess the potential habitability of planetary bodies across the Solar System and beyond. We first consider the chemical requirements of life and potential feedback effects that the presence of life can have on habitable conditions, and then the planetary, stellar, and temporal requirements for habitability. We then review the state of knowledge on the potential habitability of bodies across the Solar System and exoplanets, with a particular focus on Mars, Venus, Europa, and Enceladus. While reviewing the case for the potential habitability of each body, we summarize the most prominent and impactful studies that have informed the perspective on where habitable environments are likely to be found.
Collapse
Affiliation(s)
- M J Styczinski
- University of Washington, Seattle, Washington, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Z S Cooper
- University of Washington, Seattle, Washington, USA
| | - D M Glaser
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA
| | - O Lehmer
- NASA Ames Research Center, Moffett Field, California, USA
| | - V Mierzejewski
- School of Earth and Space Exploration, Arizona State University, Arizona, USA
| | - J Tarnas
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| |
Collapse
|
2
|
Schaible MJ, Szeinbaum N, Bozdag GO, Chou L, Grefenstette N, Colón-Santos S, Rodriguez LE, Styczinski MJ, Thweatt JL, Todd ZR, Vázquez-Salazar A, Adams A, Araújo MN, Altair T, Borges S, Burton D, Campillo-Balderas JA, Cangi EM, Caro T, Catalano E, Chen K, Conlin PL, Cooper ZS, Fisher TM, Fos SM, Garcia A, Glaser DM, Harman CE, Hermis NY, Hooks M, Johnson-Finn K, Lehmer O, Hernández-Morales R, Hughson KHG, Jácome R, Jia TZ, Marlow JJ, McKaig J, Mierzejewski V, Muñoz-Velasco I, Nural C, Oliver GC, Penev PI, Raj CG, Roche TP, Sabuda MC, Schaible GA, Sevgen S, Sinhadc P, Steller LH, Stelmach K, Tarnas J, Tavares F, Trubl G, Vidaurri M, Vincent L, Weber JM, Weng MM, Wilpiszeki RL, Young A. Chapter 1: The Astrobiology Primer 3.0. ASTROBIOLOGY 2024; 24:S4-S39. [PMID: 38498816 DOI: 10.1089/ast.2021.0129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
The Astrobiology Primer 3.0 (ABP3.0) is a concise introduction to the field of astrobiology for students and others who are new to the field of astrobiology. It provides an entry into the broader materials in this supplementary issue of Astrobiology and an overview of the investigations and driving hypotheses that make up this interdisciplinary field. The content of this chapter was adapted from the other 10 articles in this supplementary issue and thus represents the contribution of all the authors who worked on these introductory articles. The content of this chapter is not exhaustive and represents the topics that the authors found to be the most important and compelling in a dynamic and changing field.
Collapse
Affiliation(s)
- Micah J Schaible
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Nadia Szeinbaum
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - G Ozan Bozdag
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Luoth Chou
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- Center for Space Sciences and Technology, University of Maryland, Baltimore, Maryland, USA
- Georgetown University, Washington DC, USA
| | - Natalie Grefenstette
- Santa Fe Institute, Santa Fe, New Mexico, USA
- Blue Marble Space Institute of Science, Seattle, Washington, USA
| | - Stephanie Colón-Santos
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Wisconsin, USA
- Department of Botany, University of Wisconsin-Madison, Wisconsin, USA
| | - Laura E Rodriguez
- Lunar and Planetary Institute, Universities Space Research Association, Houston, Texas, USA
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - M J Styczinski
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
- University of Washington, Seattle, Washington, USA
| | - Jennifer L Thweatt
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania, USA
| | - Zoe R Todd
- Department of Earth and Space Sciences, University of Washington, Seattle, Washington, USA
| | - Alberto Vázquez-Salazar
- Departamento de Biología Evolutiva, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Department of Chemical and Biomolecular Engineering, University of California Los Angeles, California, USA
| | - Alyssa Adams
- Center for Space Sciences and Technology, University of Maryland, Baltimore, Maryland, USA
| | - M N Araújo
- Biochemistry Department, University of São Paulo, São Carlos, Brazil
| | - Thiago Altair
- Institute of Chemistry of São Carlos, Universidade de São Paulo, São Carlos, Brazil
- Department of Chemistry, College of the Atlantic, Bar Harbor, Maine, USA
| | | | - Dana Burton
- Department of Anthropology, George Washington University, Washington DC, USA
| | | | - Eryn M Cangi
- Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, Colorado, USA
| | - Tristan Caro
- Department of Geological Sciences, University of Colorado Boulder, Boulder, Colorado, USA
| | - Enrico Catalano
- Sant'Anna School of Advanced Studies, The BioRobotics Institute, Pisa, Italy
| | - Kimberly Chen
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Peter L Conlin
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Z S Cooper
- Department of Earth and Space Sciences, University of Washington, Seattle, Washington, USA
| | - Theresa M Fisher
- School of Earth and Space Exploration, Arizona State University, Tempe, Arizona, USA
| | - Santiago Mestre Fos
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Amanda Garcia
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin, USA
| | - D M Glaser
- Arizona State University, Tempe, Arizona, USA
| | - Chester E Harman
- Departamento de Biología Evolutiva, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Ninos Y Hermis
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
- Department of Physics and Space Sciences, University of Granada, Granada, Spain
| | - M Hooks
- NASA Johnson Space Center, Houston, Texas, USA
| | - K Johnson-Finn
- Earth-Life Science Institute, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, Japan
- Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Owen Lehmer
- Department of Earth and Space Sciences, University of Washington, Seattle, Washington, USA
| | - Ricardo Hernández-Morales
- Departamento de Biología Evolutiva, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Kynan H G Hughson
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Rodrigo Jácome
- Departamento de Biología Evolutiva, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Tony Z Jia
- Blue Marble Space Institute of Science, Seattle, Washington, USA
- Earth-Life Science Institute, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, Japan
| | - Jeffrey J Marlow
- Department of Biology, Boston University, Boston, Massachusetts, USA
| | - Jordan McKaig
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Veronica Mierzejewski
- School of Earth and Space Exploration, Arizona State University, Tempe, Arizona, USA
| | - Israel Muñoz-Velasco
- Departamento de Biología Evolutiva, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Ceren Nural
- Istanbul Technical University, Istanbul, Turkey
| | - Gina C Oliver
- Department of Geology, San Bernardino Valley College, San Bernardino, California, USA
| | - Petar I Penev
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Chinmayee Govinda Raj
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Tyler P Roche
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Mary C Sabuda
- Department of Earth and Environmental Sciences, University of Minnesota-Twin Cities, Minneapolis, Minnesota, USA
- Biotechnology Institute, University of Minnesota-Twin Cities, St. Paul, Minnesota, USA
| | - George A Schaible
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Serhat Sevgen
- Blue Marble Space Institute of Science, Seattle, Washington, USA
- Institute of Marine Sciences, Middle East Technical University, Erdemli, Mersin, Turkey
| | - Pritvik Sinhadc
- BEYOND: Center For Fundamental Concepts in Science, Arizona State University, Arizona, USA
- Dubai College, Dubai, United Arab Emirates
| | - Luke H Steller
- Australian Centre for Astrobiology, and School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, Australia
| | - Kamil Stelmach
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, USA
| | - J Tarnas
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Frank Tavares
- Space Enabled Research Group, MIT Media Lab, Cambridge, Massachusetts, USA
| | - Gareth Trubl
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Monica Vidaurri
- Center for Space Sciences and Technology, University of Maryland, Baltimore, Maryland, USA
- Department of Physics and Astronomy, Howard University, Washington DC, USA
| | - Lena Vincent
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Wisconsin, USA
| | - Jessica M Weber
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | | | | | - Amber Young
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- Northern Arizona University, Flagstaff, Arizona, USA
| |
Collapse
|
3
|
Emran A, Dalle Ore CM, Ahrens CJ, Khan MKH, Chevrier VF, Cruikshank DP. Pluto’s Surface Mapping Using Unsupervised Learning from Near-infrared Observations of LEISA/Ralph. THE PLANETARY SCIENCE JOURNAL 2023; 4:15. [DOI: 10.3847/psj/acb0cc] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Abstract
We map the surface of Pluto using an unsupervised machine-learning technique using the near-infrared observations of the LEISA/Ralph instrument on board NASA’s New Horizons spacecraft. The principal-component-reduced Gaussian mixture model was implemented to investigate the geographic distribution of the surface units across the dwarf planet. We also present the likelihood of each surface unit at the image pixel level. Average I/F spectra of each unit were analyzed—in terms of the position and strengths of absorption bands of abundant volatiles such as N2, CH4, and CO and nonvolatile H2O—to connect the unit to surface composition, geology, and geographic location. The distribution of surface units shows a latitudinal pattern with distinct surface compositions of volatiles—consistent with the existing literature. However, previous mapping efforts were based primarily on compositional analysis using spectral indices (indicators) or implementation of complex radiative transfer models, which need (prior) expert knowledge, label data, or optical constants of representative end-members. We prove that an application of unsupervised learning in this instance renders a satisfactory result in mapping the spatial distribution of ice compositions without any prior information or label data. Thus, such an application is specifically advantageous for a planetary surface mapping when label data are poorly constrained or completely unknown, because an understanding of surface material distribution is vital for volatile transport modeling at the planetary scale. We emphasize that the unsupervised learning used in this study has wide applicability and can be expanded to other planetary bodies of the solar system for mapping surface material distribution.
Collapse
|
4
|
Endogenically sourced volatiles on Charon and other Kuiper belt objects. Nat Commun 2022; 13:4457. [PMID: 35945207 PMCID: PMC9363412 DOI: 10.1038/s41467-022-31846-8] [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: 09/25/2021] [Accepted: 07/01/2022] [Indexed: 11/18/2022] Open
Abstract
Kuiper belt objects (KBOs) have diverse surface compositions, and the New Horizons mission to the Pluto-Charon system allows us to test hypotheses on the origin and evolution of these KBO surfaces. Previous work proposed that Charon’s organic-rich north pole formed from radiolytically processed volatiles sourced from Pluto’s escaping atmosphere. Here, we show an endogenic source of volatiles from Charon’s interior is plausible. We calculate that cryovolcanic resurfacing released 1.29 × 1015–3.47 × 1015 kg of methane to Charon’s surface from its interior. We modeled volatile transport and found the vast majority of this volcanically released methane migrates to Charon’s poles, with deposition rates sufficient to be processed into the observed organic compounds. Irradiated methane products appear on similarly sized KBOs that do not orbit a Pluto-sized object to draw an escaping atmosphere from, so interior-sourced volatiles could be a common and important process across the Kuiper belt. We show cryovolcanic eruptions released sufficient methane to source volatile products on Charon. Irradiated methane products are found on other Kuiper belt objects, so endogenically sourced volatiles could be important across the Kuiper belt.
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Singer KN, White OL, Schmitt B, Rader EL, Protopapa S, Grundy WM, Cruikshank DP, Bertrand T, Schenk PM, McKinnon WB, Stern SA, Dhingra RD, Runyon KD, Beyer RA, Bray VJ, Ore CD, Spencer JR, Moore JM, Nimmo F, Keane JT, Young LA, Olkin CB, Lauer TR, Weaver HA, Ennico-Smith K. Large-scale cryovolcanic resurfacing on Pluto. Nat Commun 2022; 13:1542. [PMID: 35351895 PMCID: PMC8964750 DOI: 10.1038/s41467-022-29056-3] [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: 06/23/2021] [Accepted: 02/09/2022] [Indexed: 11/09/2022] Open
Abstract
The New Horizons spacecraft returned images and compositional data showing that terrains on Pluto span a variety of ages, ranging from relatively ancient, heavily cratered areas to very young surfaces with few-to-no impact craters. One of the regions with very few impact craters is dominated by enormous rises with hummocky flanks. Similar features do not exist anywhere else in the imaged solar system. Here we analyze the geomorphology and composition of the features and conclude this region was resurfaced by cryovolcanic processes, of a type and scale so far unique to Pluto. Creation of this terrain requires multiple eruption sites and a large volume of material (>104 km3) to form what we propose are multiple, several-km-high domes, some of which merge to form more complex planforms. The existence of these massive features suggests Pluto’s interior structure and evolution allows for either enhanced retention of heat or more heat overall than was anticipated before New Horizons, which permitted mobilization of water-ice-rich materials late in Pluto’s history. Giant icy volcanos (cryovolcanos) on Pluto are unique in the imaged solar system and provide evidence for unexpected, active geology late in Pluto’s history.
Collapse
|
7
|
Abstract
Ground-based telescopes and space exploration have provided outstanding observations of the complexity of icy planetary surfaces. This work presents our review of the varying nature of carbon dioxide (CO2) and carbon monoxide (CO) ices from the cold traps on the Moon to Pluto in the Kuiper Belt. This review is organized into five parts. First, we review the mineral physics (e.g., rheology) relevant to these environments. Next, we review the radiation-induced chemical processes and the current interpretation of spectral signatures. The third section discusses the nature and distribution of CO2 in the giant planetary systems of Jupiter and Saturn, which are much better understood than the satellites of Uranus and Neptune, discussed in the subsequent section. The final sections focus on Pluto in comparison to Triton, having mainly CO, and a brief overview of cometary materials. We find that CO2 ices exist on many of these icy bodies by way of magnetospheric influence, while intermixing into solid ices with CH4 (methane) and N2 (nitrogen) out to Triton and Pluto. Such radiative mechanisms or intermixing can provide a wide diversity of icy surfaces, though we conclude where further experimental research of these ices is still needed.
Collapse
|
8
|
Kleimeier NF, Liu Y, Turner AM, Young LA, Chin CH, Yang T, He X, Lo JI, Cheng BM, Kaiser RI. Excited state photochemically driven surface formation of benzene from acetylene ices on Pluto and in the outer solar system. Phys Chem Chem Phys 2022; 24:1424-1436. [PMID: 34982080 DOI: 10.1039/d1cp04959c] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
NASA's New Horizons mission unveiled a diverse landscape of Pluto's surface with massive regions being neutral in color, while others like Cthulhu Macula range from golden-yellow to reddish comprising up to half of Pluto's carbon budget. Here, we demonstrate in laboratory experiments merged with electronic structure calculations that the photolysis of solid acetylene - the most abundant precipitate on Pluto's surface - by low energy ultraviolet photons efficiently synthesizes benzene and polycyclic aromatic hydrocarbons via excited state photochemistry thus providing critical molecular building blocks for the colored surface material. Since low energy photons deliver doses to Pluto's surface exceeding those from cosmic rays by six orders of magnitude, these processes may significantly contribute to the coloration of Pluto's surface and of hydrocarbon-covered surfaces of Solar System bodies such as Triton in general. This discovery critically enhances our perception of the distribution of aromatic molecules and carbon throughout our Solar System.
Collapse
Affiliation(s)
- N Fabian Kleimeier
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. .,Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Yiwei Liu
- State Key Laboratory of Precision Spectroscopy, Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, P. R. China.
| | - Andrew M Turner
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. .,Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Leslie A Young
- Southwest Research Institute, Department of Space Studies, Boulder, CO 80302, USA
| | - Chih-Hao Chin
- State Key Laboratory of Precision Spectroscopy, Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, P. R. China.
| | - Tao Yang
- State Key Laboratory of Precision Spectroscopy, Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, P. R. China. .,Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, P. R. China
| | - Xiao He
- State Key Laboratory of Precision Spectroscopy, Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, P. R. China. .,New York University - East China Normal University Center for Computational Chemistry, New York University, Shanghai 200062, P. R. China.
| | - Jen-Iu Lo
- Department of Medical Research, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien City 970, Taiwan
| | - Bing-Ming Cheng
- Department of Medical Research, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien City 970, Taiwan.,Tzu-Chi University of Science and Technology, Hualien City 970, Taiwan
| | - Ralf I Kaiser
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. .,Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| |
Collapse
|
9
|
Morison A, Labrosse S, Choblet G. Sublimation-driven convection in Sputnik Planitia on Pluto. Nature 2021; 600:419-423. [PMID: 34912087 DOI: 10.1038/s41586-021-04095-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 10/04/2021] [Indexed: 11/09/2022]
Abstract
Sputnik Planitia is a nitrogen-ice-filled basin on Pluto1. Its polygonal surface patterns2 have been previously explained as a result of solid-state convection with either an imposed heat flow3 or a temperature difference within the 10-km-thick ice layer4. Neither explanation is satisfactory, because they do not exhibit surface topography with the observed pattern: flat polygons delimited by narrow troughs5. Internal heating produces the observed patterns6, but the heating source in such a setup remains enigmatic. Here we report the results of modelling the effects of sublimation at the surface. We find that sublimation-driven convection readily produces the observed polygonal structures if we assume a smaller heat flux (~0.3 mW m-2) at the base of the ice layer than the commonly accepted value of 2-3 mW m-2 (ref. 7). Sustaining this regime with the latter value is also possible, but would require a stronger viscosity contrast (~3,000) than the nominal value (~100) considered in this study.
Collapse
Affiliation(s)
| | | | - Gaël Choblet
- Laboratoire de Planétologie et Géodynamique, UMR 6112, Nantes Université, CNRS, Université d'Angers, Nantes, France
| |
Collapse
|
10
|
Schenk PM, Moore JM. Topography and geology of Uranian mid-sized icy satellites in comparison with Saturnian and Plutonian satellites. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20200102. [PMID: 33161858 DOI: 10.1098/rsta.2020.0102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/03/2020] [Indexed: 05/20/2023]
Abstract
Newly processed global imaging and topographic mapping of Uranus's five major satellites reveal differences and similarities to mid-sized satellites at Saturn and Pluto. Three modes of internal heat redistribution are recognized. The broad similarity of Miranda's three oval resurfacing zones to those mapped on Enceladus and (subtly) on Dione are likely due to antipodal diapiric upwelling. Conversely, break-up and foundering of crustal blocks accompanied by extensive (cryo)volcanism is the dominant mode on both Charon and Ariel. Titania's fault network finds parallels on Rhea, Dione, Tethys and possibly Oberon. Differences in the geologic style of resurfacing in the satellite systems (e.g. plains on Charon, Dione, Tethys and perhaps Titania versus ridges on Miranda and Ariel) may be driven by differences in ice composition. Surface processes such as volatile transport may also be indicated by bright and dark materials on Oberon, Umbriel and Charon. The more complete and higher quality observations of the Saturnian and Plutonian mid-sized icy satellites by Cassini and New Horizons reveal a wealth of features and phenomena that cannot be perceived in the more limited Voyager coverage of the Uranian satellites, harbingers of many discoveries awaiting us on a return to Uranus. This article is part of a discussion meeting issue 'Future exploration of ice giant systems'.
Collapse
Affiliation(s)
- Paul M Schenk
- Lunar and Planteray Institute/USRA, Houston, TX, USA
| | | |
Collapse
|
11
|
Bertrand T, Forget F, Schmitt B, White OL, Grundy WM. Equatorial mountains on Pluto are covered by methane frosts resulting from a unique atmospheric process. Nat Commun 2020; 11:5056. [PMID: 33051457 PMCID: PMC7553927 DOI: 10.1038/s41467-020-18845-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 09/08/2020] [Indexed: 12/01/2022] Open
Abstract
Pluto is covered by numerous deposits of methane, either diluted in nitrogen or as methane-rich ice. Within the dark equatorial region of Cthulhu, bright frost containing methane is observed coating crater rims and walls as well as mountain tops, providing spectacular resemblance to terrestrial snow-capped mountain chains. However, the origin of these deposits remained enigmatic. Here we report that they are composed of methane-rich ice. We use high-resolution numerical simulations of Pluto’s climate to show that the processes forming them are likely to be completely different to those forming high-altitude snowpack on Earth. The methane deposits may not result from adiabatic cooling in upwardly moving air like on our planet, but from a circulation-induced enrichment of gaseous methane a few kilometres above Pluto’s plains that favours methane condensation at mountain summits. This process could have shaped other methane reservoirs on Pluto and help explain the appearance of the bladed terrain of Tartarus Dorsa. Pluto is covered by numerous deposits of methane. Here, the authors show that the formation of methane frost on mountain tops and crater rims in Pluto’s equatorial regions completely differ from those forming snow-capped mountains on Earth.
Collapse
Affiliation(s)
- Tanguy Bertrand
- National Aeronautics and Space Administration (NASA), Ames Research Center, Space Science Division, Moffett Field, CA, 94035, USA. .,Laboratoire de Météorologie Dynamique, IPSL, Sorbonne Universités, UPMC Université Paris 06, CNRS, BP99, 4 place Jussieu, 75005, Paris, France.
| | - François Forget
- Laboratoire de Météorologie Dynamique, IPSL, Sorbonne Universités, UPMC Université Paris 06, CNRS, BP99, 4 place Jussieu, 75005, Paris, France.
| | - Bernard Schmitt
- Université Grenoble Alpes, CNRS, Institut de Planétologie et d'Astrophysique de Grenoble, 38000, Grenoble, France
| | - Oliver L White
- National Aeronautics and Space Administration (NASA), Ames Research Center, Space Science Division, Moffett Field, CA, 94035, USA.,The SETI Institute, Mountain View, CA, 94043, USA
| | | |
Collapse
|
12
|
Salzmann CG, Rosu-Finsen A. The crystallography of Pluto. IUCRJ 2020; 7:782-783. [PMID: 32939269 PMCID: PMC7467172 DOI: 10.1107/s205225252001163x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Maynard-Casely and co-workers [IUCrJ (2020). 7, 844-851.] investigate two of Pluto's most abundant minerals with neutron diffraction. The new results will be key to understanding the geology of our distant neighbour and represent a significant advance in the emerging field of small-molecule geology.
Collapse
Affiliation(s)
- Christoph G. Salzmann
- University College London, Department of Chemistry, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Alexander Rosu-Finsen
- University College London, Department of Chemistry, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| |
Collapse
|
13
|
Maynard-Casely HE, Hester JR, Brand HEA. Re-examining the crystal structure behaviour of nitrogen and methane. IUCRJ 2020; 7:844-851. [PMID: 32939276 PMCID: PMC7467175 DOI: 10.1107/s2052252520007460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 06/04/2020] [Indexed: 06/11/2023]
Abstract
In the light of NASA's New Horizons mission, the solid-phase behaviour of methane and nitrogen has been re-examined and the thermal expansion coefficients of both materials have been determined over their whole solid temperature range for the first time. Neutron diffraction results indicate that the symmetric Pa 3 space group is the best description for the α-nitrogen structure, rather than the long-accepted P213. Furthermore, it is also observed that β-nitrogen and methane phase I show changes in texture on warming, indicating grain growth.
Collapse
Affiliation(s)
- Helen E. Maynard-Casely
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC 2232 Australia
| | - James R. Hester
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC 2232 Australia
| | - Helen E. A. Brand
- Australian Synchrotron, ANSTO, 800 Blackburn Road, Clayton 3168, Australia
| |
Collapse
|
14
|
Cruikshank DP, Materese CK, Pendleton YJ, Boston PJ, Grundy WM, Schmitt B, Lisse CM, Runyon KD, Keane JT, Beyer RA, Summers ME, Scipioni F, Stern SA, Dalle Ore CM, Olkin CB, Young LA, Ennico K, Weaver HA, Bray VJ. Prebiotic Chemistry of Pluto. ASTROBIOLOGY 2019; 19:831-848. [PMID: 30907634 DOI: 10.1089/ast.2018.1927] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present the case for the presence of complex organic molecules, such as amino acids and nucleobases, formed by abiotic processes on the surface and in near-subsurface regions of Pluto. Pluto's surface is tinted with a range of non-ice substances with colors ranging from light yellow to red to dark brown; the colors match those of laboratory organic residues called tholins. Tholins are broadly characterized as complex, macromolecular organic solids consisting of a network of aromatic structures connected by aliphatic bridging units (e.g., Imanaka et al., 2004; Materese et al., 2014, 2015). The synthesis of tholins in planetary atmospheres and in surface ices has been explored in numerous laboratory experiments, and both gas- and solid-phase varieties are found on Pluto. A third variety of tholins, exposed at a site of tectonic surface fracturing called Virgil Fossae, appears to have come from a reservoir in the subsurface. Eruptions of tholin-laden liquid H2O from a subsurface aqueous repository appear to have covered portions of Virgil Fossae and its surroundings with a uniquely colored deposit (D.P. Cruikshank, personal communication) that is geographically correlated with an exposure of H2O ice that includes spectroscopically detected NH3 (C.M. Dalle Ore, personal communication). The subsurface organic material could have been derived from presolar or solar nebula processes, or might have formed in situ. Photolysis and radiolysis of a mixture of ices relevant to Pluto's surface composition (N2, CH4, CO) have produced strongly colored, complex organics with a significant aromatic content having a high degree of nitrogen substitution similar to the aromatic heterocycles pyrimidine and purine (Materese et al., 2014, 2015; Cruikshank et al., 2016). Experiments with pyrimidines and purines frozen in H2O-NH3 ice resulted in the formation of numerous nucleobases, including the biologically relevant guanine, cytosine, adenine, uracil, and thymine (Materese et al., 2017). The red material associated with the H2O ice may contain nucleobases resulting from energetic processing on Pluto's surface or in the interior. Some other Kuiper Belt objects also exhibit red colors similar to those found on Pluto and may therefore carry similar inventories of complex organic materials. The widespread and ubiquitous nature of similarly complex organic materials observed in a variety of astronomical settings drives the need for additional laboratory and modeling efforts to explain the origin and evolution of organic molecules. Pluto observations reveal complex organics on a small body that remains close to its place of origin in the outermost regions of the Solar System.
Collapse
Affiliation(s)
- D P Cruikshank
- 1NASA Ames Research Center, Moffett Field, California, USA
| | - C K Materese
- 2Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - Y J Pendleton
- 1NASA Ames Research Center, Moffett Field, California, USA
| | - P J Boston
- 1NASA Ames Research Center, Moffett Field, California, USA
| | - W M Grundy
- 3Lowell Observatory, Flagstaff, Arizona, USA
| | - B Schmitt
- 4Université Grenoble Alpes, CNRS, IPAG, Grenoble, France
| | - C M Lisse
- 5Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland, USA
| | - K D Runyon
- 5Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland, USA
| | - J T Keane
- 6California Institute of Technology, Pasadena, California, USA
| | - R A Beyer
- 1NASA Ames Research Center, Moffett Field, California, USA
| | - M E Summers
- 7Department of Physics and Astronomy, George Mason University, Fairfax, Virginia, USA
| | - F Scipioni
- 1NASA Ames Research Center, Moffett Field, California, USA
| | - S A Stern
- 8Southwest Research Institute, Boulder, Colorado, USA
| | - C M Dalle Ore
- 1NASA Ames Research Center, Moffett Field, California, USA
| | - C B Olkin
- 8Southwest Research Institute, Boulder, Colorado, USA
| | - L A Young
- 8Southwest Research Institute, Boulder, Colorado, USA
| | - K Ennico
- 1NASA Ames Research Center, Moffett Field, California, USA
| | - H A Weaver
- 5Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland, USA
| | - V J Bray
- 9Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, USA
| |
Collapse
|
15
|
Abrahams JNH, Nimmo F. Ferrovolcanism: Iron Volcanism on Metallic Asteroids. GEOPHYSICAL RESEARCH LETTERS 2019; 46:5055-5064. [PMID: 32020958 PMCID: PMC6999792 DOI: 10.1029/2019gl082542] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 03/07/2019] [Indexed: 06/02/2023]
Abstract
Metallic asteroids, the exposed cores of disrupted planetesimals, are expected to have been exposed while still molten. Some would have cooled from the outside in, crystallizing a surface crust which would then grow inward. Because the growing crust is expected to be more dense than the underlying melt, this melt will tend to migrate toward the surface whenever it is able. Compressional stresses produced in the crust while it cools will be relieved locally by thrust faulting, which will also provide potential conduits for melt to reach the surface. We predict iron volcanism to have occurred on metallic asteroids as they cooled and discuss the implications of this process for both the evolution and the modern appearance of these bodies.
Collapse
Affiliation(s)
- Jacob N H Abrahams
- Department of Earth and Planetary Science, University of California Santa Cruz, Santa Cruz, CA 95064
| | - Francis Nimmo
- Department of Earth and Planetary Science, University of California Santa Cruz, Santa Cruz, CA 95064
| |
Collapse
|
16
|
Dalle Ore CM, Cruikshank DP, Protopapa S, Scipioni F, McKinnon WB, Cook JC, Grundy WM, Schmitt B, Stern SA, Moore JM, Verbiscer A, Parker AH, Singer KN, Umurhan OM, Weaver HA, Olkin CB, Young LA, Ennico K. Detection of ammonia on Pluto's surface in a region of geologically recent tectonism. SCIENCE ADVANCES 2019; 5:eaav5731. [PMID: 31608308 PMCID: PMC6771079 DOI: 10.1126/sciadv.aav5731] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 04/25/2019] [Indexed: 06/10/2023]
Abstract
We report the detection of ammonia (NH3) on Pluto's surface in spectral images obtained with the New Horizons spacecraft that show absorption bands at 1.65 and 2.2 μm. The ammonia signature is spatially coincident with a region of past extensional tectonic activity (Virgil Fossae) where the presence of H2O ice is prominent. Ammonia in liquid water profoundly depresses the freezing point of the mixture. Ammoniated ices are believed to be geologically short lived when irradiated with ultraviolet photons or charged particles. Thus, the presence of NH3 on a planetary surface is indicative of a relatively recent deposition or possibly through exposure by some geological process. In the present case, the areal distribution is more suggestive of cryovolcanic emplacement, however, adding to the evidence for ongoing geological activity on Pluto and the possible presence of liquid water at depth today.
Collapse
Affiliation(s)
- C. M. Dalle Ore
- SETI Institute, Mountain View CA, USA
- NASA Ames Research Center, Moffett Field CA, USA
| | | | | | - F. Scipioni
- SETI Institute, Mountain View CA, USA
- NASA Ames Research Center, Moffett Field CA, USA
| | - W. B. McKinnon
- Department of Earth and Planetary Sciences and the McDonnell Center for the Space Sciences, Washington University, St. Louis, MO, USA
| | | | | | - B. Schmitt
- Université Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France
| | - S. A. Stern
- Southwest Research Institute, Boulder CO, USA
| | - J. M. Moore
- NASA Ames Research Center, Moffett Field CA, USA
| | - A. Verbiscer
- Johns Hopkins University Applied Physics Laboratory, Laurel MD, USA
| | | | | | - O. M. Umurhan
- SETI Institute, Mountain View CA, USA
- NASA Ames Research Center, Moffett Field CA, USA
| | - H. A. Weaver
- University of Virginia, Charlottesville, VA, USA
| | - C. B. Olkin
- Southwest Research Institute, Boulder CO, USA
| | - L. A. Young
- Southwest Research Institute, Boulder CO, USA
| | - K. Ennico
- NASA Ames Research Center, Moffett Field CA, USA
| |
Collapse
|
17
|
Singer KN, McKinnon WB, Gladman B, Greenstreet S, Bierhaus EB, Stern SA, Parker AH, Robbins SJ, Schenk PM, Grundy WM, Bray VJ, Beyer RA, Binzel RP, Weaver HA, Young LA, Spencer JR, Kavelaars JJ, Moore JM, Zangari AM, Olkin CB, Lauer TR, Lisse CM, Ennico K. Impact craters on Pluto and Charon indicate a deficit of small Kuiper belt objects. Science 2019; 363:955-959. [PMID: 30819958 DOI: 10.1126/science.aap8628] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 02/05/2019] [Indexed: 11/02/2022]
Abstract
The flyby of Pluto and Charon by the New Horizons spacecraft provided high-resolution images of cratered surfaces embedded in the Kuiper belt, an extensive region of bodies orbiting beyond Neptune. Impact craters on Pluto and Charon were formed by collisions with other Kuiper belt objects (KBOs) with diameters from ~40 kilometers to ~300 meters, smaller than most KBOs observed directly by telescopes. We find a relative paucity of small craters ≲13 kilometers in diameter, which cannot be explained solely by geological resurfacing. This implies a deficit of small KBOs (≲1 to 2 kilometers in diameter). Some surfaces on Pluto and Charon are likely ≳4 billion years old, thus their crater records provide information on the size-frequency distribution of KBOs in the early Solar System.
Collapse
|
18
|
Telfer MW, Parteli EJR, Radebaugh J, Beyer RA, Bertrand T, Forget F, Nimmo F, Grundy WM, Moore JM, Stern SA, Spencer J, Lauer TR, Earle AM, Binzel RP, Weaver HA, Olkin CB, Young LA, Ennico K, Runyon K, Buie M, Buratti B, Cheng A, Kavelaars JJ, Linscott I, McKinnon WB, Reitsema H, Reuter D, Schenk P, Showalter M, Tyler L. Dunes on Pluto. Science 2018; 360:992-997. [PMID: 29853681 DOI: 10.1126/science.aao2975] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 04/19/2018] [Indexed: 11/02/2022]
Abstract
The surface of Pluto is more geologically diverse and dynamic than had been expected, but the role of its tenuous atmosphere in shaping the landscape remains unclear. We describe observations from the New Horizons spacecraft of regularly spaced, linear ridges whose morphology, distribution, and orientation are consistent with being transverse dunes. These are located close to mountainous regions and are orthogonal to nearby wind streaks. We demonstrate that the wavelength of the dunes (~0.4 to 1 kilometer) is best explained by the deposition of sand-sized (~200 to ~300 micrometer) particles of methane ice in moderate winds (<10 meters per second). The undisturbed morphology of the dunes, and relationships with the underlying convective glacial ice, imply that the dunes have formed in the very recent geological past.
Collapse
Affiliation(s)
- Matt W Telfer
- School of Geography, Earth and Environmental Sciences, Plymouth University, Drake Circus, Plymouth, Devon PL4 8AA, UK.
| | - Eric J R Parteli
- Department of Geosciences, University of Cologne, Pohligstraße 3, 50969 Cologne, Germany
| | - Jani Radebaugh
- Department of Geological Sciences, College of Physical and Mathematical Sciences, Brigham Young University, Provo, UT 84602, USA
| | - Ross A Beyer
- Sagan Center at the SETI Institute, Mountain View, CA 94043, USA.,NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - Tanguy Bertrand
- Laboratoire de Météorologie Dynamique, Université Pierre et Marie Curie, Paris, France
| | - François Forget
- Laboratoire de Météorologie Dynamique, Université Pierre et Marie Curie, Paris, France
| | - Francis Nimmo
- University of California Santa Cruz, Santa Cruz, CA, USA
| | | | | | | | | | - Tod R Lauer
- National Optical Astronomy Observatory, Tucson, AZ 85726, USA
| | - Alissa M Earle
- Department of Earth, Atmosphere, and Planetary Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Richard P Binzel
- Department of Earth, Atmosphere, and Planetary Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Hal A Weaver
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - Cathy B Olkin
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | | | | | - Kirby Runyon
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Pavithraa S, Lo JI, Rahul K, Raja Sekhar BN, Cheng BM, Mason NJ, Sivaraman B. Vacuum ultraviolet photoabsorption of prime ice analogues of Pluto and Charon. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 190:172-176. [PMID: 28922643 DOI: 10.1016/j.saa.2017.08.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 08/23/2017] [Accepted: 08/24/2017] [Indexed: 06/07/2023]
Abstract
Here we present the first Vacuum UltraViolet (VUV) photoabsorption spectra of ice analogues of Pluto and Charon ice mixtures. For Pluto the ice analogue is an icy mixture containing nitrogen (N2), carbon monoxide (CO), methane (CH4) and water (H2O) prepared with a 100:1:1:3 ratio, respectively. Photoabsorption of icy mixtures with and without H2O were recorded and no significant changes in the spectra due to presence of H2O were observed. For Charon a VUV photoabsorption spectra of an ice analogue containing ammonia (NH3) and H2O prepared with a 1:1 ratio was recorded, a spectrum of ammonium hydroxide (NH4OH) was also recorded. These spectra may help to interpret the P-Alice data from New Horizons.
Collapse
Affiliation(s)
- S Pavithraa
- Physical Research Laboratory, Ahmedabad 380 009, India
| | - J-I Lo
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - K Rahul
- Physical Research Laboratory, Ahmedabad 380 009, India
| | - B N Raja Sekhar
- Atomic and Molecular Physics Division, BARC at RRCAT, Indore 452 013, India
| | - B-M Cheng
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - N J Mason
- Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK
| | - B Sivaraman
- Physical Research Laboratory, Ahmedabad 380 009, India.
| |
Collapse
|
20
|
Vance SD, Kedar S, Panning MP, Stähler SC, Bills BG, Lorenz RD, Huang HH, Pike WT, Castillo JC, Lognonné P, Tsai VC, Rhoden AR. Vital Signs: Seismology of Icy Ocean Worlds. ASTROBIOLOGY 2018; 18:37-53. [PMID: 29345986 DOI: 10.1089/ast.2016.1612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Ice-covered ocean worlds possess diverse energy sources and associated mechanisms that are capable of driving significant seismic activity, but to date no measurements of their seismic activity have been obtained. Such investigations could reveal the transport properties and radial structures, with possibilities for locating and characterizing trapped liquids that may host life and yielding critical constraints on redox fluxes and thus on habitability. Modeling efforts have examined seismic sources from tectonic fracturing and impacts. Here, we describe other possible seismic sources, their associations with science questions constraining habitability, and the feasibility of implementing such investigations. We argue, by analogy with the Moon, that detectable seismic activity should occur frequently on tidally flexed ocean worlds. Their ices fracture more easily than rocks and dissipate more tidal energy than the <1 GW of the Moon and Mars. Icy ocean worlds also should create less thermal noise due to their greater distance and consequently smaller diurnal temperature variations. They also lack substantial atmospheres (except in the case of Titan) that would create additional noise. Thus, seismic experiments could be less complex and less susceptible to noise than prior or planned planetary seismology investigations of the Moon or Mars. Key Words: Seismology-Redox-Ocean worlds-Europa-Ice-Hydrothermal. Astrobiology 18, 37-53.
Collapse
Affiliation(s)
- Steven D Vance
- 1 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California, USA
| | - Sharon Kedar
- 1 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California, USA
| | - Mark P Panning
- 1 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California, USA
| | - Simon C Stähler
- 2 Institute of Geophysics , ETH Zürich, Zürich, Switzerland
- 3 Leibniz-Institute for Baltic Sea Research (IOW) , Rostock, Germany
| | - Bruce G Bills
- 1 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California, USA
| | - Ralph D Lorenz
- 4 Johns Hopkins Applied Physics Laboratory , Laurel, Maryland, USA
| | - Hsin-Hua Huang
- 5 Institute of Earth Sciences , Academia Sinica, Taipei, Taiwan
- 6 Seismological Laboratory, California Institute of Technology , Pasadena, California, USA
| | - W T Pike
- 7 Optical and Semiconductor Devices Group, Department of Electrical and Electronic Engineering, Imperial College , London, UK
| | - Julie C Castillo
- 1 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California, USA
| | - Philippe Lognonné
- 8 Univ Paris Diderot-Sorbonne Paris Cité, Institut de Physique du Globe de Paris , Paris, France
| | - Victor C Tsai
- 6 Seismological Laboratory, California Institute of Technology , Pasadena, California, USA
| | - Alyssa R Rhoden
- 9 School of Earth and Space Exploration, Arizona State University , Tempe, Arizona, USA
| |
Collapse
|
21
|
Black BA, Perron JT, Hemingway D, Bailey E, Nimmo F, Zebker H. Global drainage patterns and the origins of topographic relief on Earth, Mars, and Titan. Science 2017; 356:727-731. [PMID: 28522528 DOI: 10.1126/science.aag0171] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 04/06/2017] [Indexed: 11/02/2022]
Abstract
Rivers have eroded the topography of Mars, Titan, and Earth, creating diverse landscapes. However, the dominant processes that generated topography on Titan (and to some extent on early Mars) are not well known. We analyzed drainage patterns on all three bodies and found that large drainages, which record interactions between deformation and erosional modification, conform much better to long-wavelength topography on Titan and Mars than on Earth. We use a numerical landscape evolution model to demonstrate that short-wavelength deformation causes drainage directions to diverge from long-wavelength topography, as observed on Earth. We attribute the observed differences to ancient long-wavelength topography on Mars, recent or ongoing generation of long-wavelength relief on Titan, and the creation of short-wavelength relief by plate tectonics on Earth.
Collapse
Affiliation(s)
- Benjamin A Black
- Department of Earth and Atmospheric Science, City College of New York, City University of New York, New York, NY, USA. .,Earth and Environmental Science, The Graduate Center, City University of New York, New York, NY, USA
| | - J Taylor Perron
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Douglas Hemingway
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, USA.
| | - Elizabeth Bailey
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Francis Nimmo
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Howard Zebker
- Department of Geophysics, School of Earth Sciences, Stanford University, Stanford, CA, USA
| |
Collapse
|
22
|
Gilbert AJ, Oppong FK, Farr RS. Flow and evolution of ice-sucrose crystal mushes. Phys Rev E 2017; 95:042606. [PMID: 28505788 DOI: 10.1103/physreve.95.042606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Indexed: 11/07/2022]
Abstract
We study the rheology of suspensions of ice crystals at moderate to high volume fractions in a sucrose solution in which they are partially soluble, a model system for a wide class of crystal mushes or slurries. Under step changes in shear rate, the viscosity changes to a relaxed value over several minutes, in a manner well fitted by a single exponential. The behavior of the relaxed viscosity is power-law shear thinning with shear rate, with an exponent of -1.76±0.25, so that shear stress falls with increasing shear rate. On longer time scales, the crystals ripen (leading to a falling viscosity) so that the mean radius increases with time to the power 0.14±0.07. We speculate that this unusually small exponent is due to the interaction of classical ripening dynamics with abrasion or breakup under flow. We compare the rheological behavior to mechanistic models based on flow-induced aggregation and breakup of crystal clusters, finding that the exponents can be predicted from liquid phase sintering and breakup by brittle fracture.
Collapse
Affiliation(s)
- Andrew J Gilbert
- Department of Earth Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Felix K Oppong
- Unilever R&D Colworth Science Park, MK44 1LQ, Bedford, United Kingdom
| | - Robert S Farr
- Unilever R&D Colworth Science Park, MK44 1LQ, Bedford, United Kingdom
| |
Collapse
|
23
|
Beyer RA, Nimmo F, McKinnon WB, Moore JM, Binzel RP, Conrad JW, Cheng A, Ennico K, Lauer TR, Olkin C, Robbins S, Schenk P, Singer K, Spencer JR, Stern SA, Weaver H, Young L, Zangari AM. Charon tectonics. ICARUS 2017; 287:161-174. [PMID: 28919640 PMCID: PMC5599803 DOI: 10.1016/j.icarus.2016.12.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
New Horizons images of Pluto's companion Charon show a variety of terrains that display extensional tectonic features, with relief surprising for this relatively small world. These features suggest a global extensional areal strain of order 1% early in Charon's history. Such extension is consistent with the presence of an ancient global ocean, now frozen.
Collapse
Affiliation(s)
- Ross A. Beyer
- Sagan Center at the SETI Institute, 189 Berndardo Ave, Mountain View, California 94043, USA
- NASA Ames Research Center, Moffet Field, CA 94035-0001, USA
| | | | | | | | | | | | - Andy Cheng
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - K. Ennico
- NASA Ames Research Center, Moffet Field, CA 94035-0001, USA
| | - Tod R. Lauer
- National Optical Astronomy Observatories, Tucson, AZ 85719, USA
| | - C.B. Olkin
- Southwest Research Institute, Boulder, CO 80302, USA
| | | | - Paul Schenk
- Lunar and Planetary Institute, Houston, TX 77058, USA
| | - Kelsi Singer
- Southwest Research Institute, Boulder, CO 80302, USA
| | | | - S. Alan Stern
- Southwest Research Institute, Boulder, CO 80302, USA
| | - H.A. Weaver
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - L.A. Young
- Southwest Research Institute, Boulder, CO 80302, USA
| | | |
Collapse
|
24
|
Penitentes as the origin of the bladed terrain of Tartarus Dorsa on Pluto. Nature 2017; 541:188-190. [PMID: 28052055 DOI: 10.1038/nature20779] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 10/31/2016] [Indexed: 11/08/2022]
Abstract
Penitentes are snow and ice features formed by erosion that, on Earth, are characterized by bowl-shaped depressions several tens of centimetres across, whose edges grade into spires up to several metres tall. Penitentes have been suggested as an explanation for anomalous radar data on Europa, but until now no penitentes have been identified conclusively on planetary bodies other than Earth. Regular ridges with spacings of 3,000 to 5,000 metres and depths of about 500 metres with morphologies that resemble penitentes have been observed by the New Horizons spacecraft in the Tartarus Dorsa region of Pluto (220°-250° E, 0°-20° N). Here we report simulations, based upon a recent model representing conditions on Pluto, in which deepening penitentes reproduce both the tri-modal (north-south, east-west and northeast-southwest) orientation and the spacing of the ridges of this bladed terrain. At present, these penitentes deepen by approximately one centimetre per orbital cycle and grow only during periods of relatively high atmospheric pressure, suggesting a formation timescale of several tens of millions of years, consistent with crater ages. This timescale implies that the penitentes formed from initial topographic variations of no more than a few tens of metres, consistent with Pluto's youngest terrains.
Collapse
|
25
|
Keane JT, Matsuyama I, Kamata S, Steckloff JK. Reorientation and faulting of Pluto due to volatile loading within Sputnik Planitia. Nature 2016; 540:90-93. [PMID: 27851731 DOI: 10.1038/nature20120] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 09/26/2016] [Indexed: 11/09/2022]
Abstract
Pluto is an astoundingly diverse, geologically dynamic world. The dominant feature is Sputnik Planitia-a tear-drop-shaped topographic depression approximately 1,000 kilometres in diameter possibly representing an ancient impact basin. The interior of Sputnik Planitia is characterized by a smooth, craterless plain three to four kilometres beneath the surrounding rugged uplands, and represents the surface of a massive unit of actively convecting volatile ices (N2, CH4 and CO) several kilometres thick. This large feature is very near the Pluto-Charon tidal axis. Here we report that the location of Sputnik Planitia is the natural consequence of the sequestration of volatile ices within the basin and the resulting reorientation (true polar wander) of Pluto. Loading of volatile ices within a basin the size of Sputnik Planitia can substantially alter Pluto's inertia tensor, resulting in a reorientation of the dwarf planet of around 60 degrees with respect to the rotational and tidal axes. The combination of this reorientation, loading and global expansion due to the freezing of a possible subsurface ocean generates stresses within the planet's lithosphere, resulting in a global network of extensional faults that closely replicate the observed fault networks on Pluto. Sputnik Planitia probably formed northwest of its present location, and was loaded with volatiles over million-year timescales as a result of volatile transport cycles on Pluto. Pluto's past, present and future orientation is controlled by feedbacks between volatile sublimation and condensation, changing insolation conditions and Pluto's interior structure.
Collapse
Affiliation(s)
- James T Keane
- Lunar and Planetary Laboratory, Department of Planetary Science, University of Arizona, Tucson, Arizona 85721, USA
| | - Isamu Matsuyama
- Lunar and Planetary Laboratory, Department of Planetary Science, University of Arizona, Tucson, Arizona 85721, USA
| | - Shunichi Kamata
- Creative Research Institution, Hokkaido University, Sapporo, Japan
| | - Jordan K Steckloff
- Purdue University, Department of Earth, Atmospheric, and Planetary Sciences, West Lafayette, Indiana 47907, USA.,Planetary Science Institute, Tucson, Arizona 85719, USA
| |
Collapse
|
26
|
Barr AC. Pluto's telltale heart. Nature 2016; 540:42-43. [DOI: 10.1038/540042a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
27
|
Observed glacier and volatile distribution on Pluto from atmosphere-topography processes. Nature 2016; 540:86-89. [PMID: 27629517 DOI: 10.1038/nature19337] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/19/2016] [Indexed: 11/08/2022]
Abstract
Pluto has a variety of surface frosts and landforms as well as a complex atmosphere. There is ongoing geological activity related to the massive Sputnik Planitia glacier, mostly made of nitrogen (N2) ice mixed with solid carbon monoxide and methane, covering the 4-kilometre-deep, 1,000-kilometre-wide basin of Sputnik Planitia near the anti-Charon point. The glacier has been suggested to arise from a source region connected to the deep interior, or from a sink collecting the volatiles released planetwide. Thin deposits of N2 frost, however, were also detected at mid-northern latitudes and methane ice was observed to cover most of Pluto except for the darker, frost-free equatorial regions. Here we report numerical simulations of the evolution of N2, methane and carbon monoxide on Pluto over thousands of years. The model predicts N2 ice accumulation in the deepest low-latitude basin and the threefold increase in atmospheric pressure that has been observed to occur since 1988. This points to atmospheric-topographic processes as the origin of Sputnik Planitia's N2 glacier. The same simulations also reproduce the observed quantities of volatiles in the atmosphere and show frosts of methane, and sometimes N2, that seasonally cover the mid- and high latitudes, explaining the bright northern polar cap reported in the 1990s and the observed ice distribution in 2015. The model also predicts that most of these seasonal frosts should disappear in the next decade.
Collapse
|
28
|
Hamilton DP, Stern SA, Moore JM, Young LA. The rapid formation of Sputnik Planitia early in Pluto's history. Nature 2016; 540:97-99. [PMID: 27905411 DOI: 10.1038/nature20586] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 10/28/2016] [Indexed: 11/09/2022]
Abstract
Pluto's Sputnik Planitia is a bright, roughly circular feature that resembles a polar ice cap. It is approximately 1,000 kilometres across and is centred on a latitude of 25 degrees north and a longitude of 175 degrees, almost directly opposite the side of Pluto that always faces Charon as a result of tidal locking. One explanation for its location includes the formation of a basin in a giant impact, with subsequent upwelling of a dense interior ocean. Once the basin was established, ice would naturally have accumulated there. Then, provided that the basin was a positive gravity anomaly (with or without the ocean), true polar wander could have moved the feature towards the Pluto-Charon tidal axis, on the far side of Pluto from Charon. Here we report modelling that shows that ice quickly accumulates on Pluto near latitudes of 30 degrees north and south, even in the absence of a basin, because, averaged over its orbital period, those are Pluto's coldest regions. Within a million years of Charon's formation, ice deposits on Pluto concentrate into a single cap centred near a latitude of 30 degrees, owing to the runaway albedo effect. This accumulation of ice causes a positive gravity signature that locks, as Pluto's rotation slows, to a longitude directly opposite Charon. Once locked, Charon raises a permanent tidal bulge on Pluto, which greatly enhances the gravity signature of the ice cap. Meanwhile, the weight of the ice in Sputnik Planitia causes the crust under it to slump, creating its own basin (as has happened on Earth in Greenland). Even if the feature is now a modest negative gravity anomaly, it remains locked in place because of the permanent tidal bulge raised by Charon. Any movement of the feature away from 30 degrees latitude is countered by the preferential recondensation of ices near the coldest extremities of the cap. Therefore, our modelling suggests that Sputnik Planitia formed shortly after Charon did and has been stable, albeit gradually losing volume, over the age of the Solar System.
Collapse
Affiliation(s)
| | | | - J M Moore
- NASA Ames, Mountain View, California, USA
| | | | | |
Collapse
|
29
|
Nimmo F, Hamilton DP, McKinnon WB, Schenk PM, Binzel RP, Bierson CJ, Beyer RA, Moore JM, Stern SA, Weaver HA, Olkin CB, Young LA, Smith KE. Reorientation of Sputnik Planitia implies a subsurface ocean on Pluto. Nature 2016; 540:94-96. [DOI: 10.1038/nature20148] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 10/03/2016] [Indexed: 11/09/2022]
|
30
|
The formation of Charon's red poles from seasonally cold-trapped volatiles. Nature 2016; 539:65-68. [PMID: 27626378 DOI: 10.1038/nature19340] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 07/13/2016] [Indexed: 11/09/2022]
Abstract
A unique feature of Pluto's large satellite Charon is its dark red northern polar cap. Similar colours on Pluto's surface have been attributed to tholin-like organic macromolecules produced by energetic radiation processing of hydrocarbons. The polar location on Charon implicates the temperature extremes that result from Charon's high obliquity and long seasons in the production of this material. The escape of Pluto's atmosphere provides a potential feedstock for a complex chemistry. Gas from Pluto that is transiently cold-trapped and processed at Charon's winter pole was proposed as an explanation for the dark coloration on the basis of an image of Charon's northern hemisphere, but not modelled quantitatively. Here we report images of the southern hemisphere illuminated by Pluto-shine and also images taken during the approach phase that show the northern polar cap over a range of longitudes. We model the surface thermal environment on Charon and the supply and temporary cold-trapping of material escaping from Pluto, as well as the photolytic processing of this material into more complex and less volatile molecules while cold-trapped. The model results are consistent with the proposed mechanism for producing the observed colour pattern on Charon.
Collapse
|
31
|
Maynard-Casely HE. ‘Peaks in space’ – crystallography in planetary science: past impacts and future opportunities. CRYSTALLOGR REV 2016. [DOI: 10.1080/0889311x.2016.1242127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
32
|
Skibba R. Giant ice volcano spotted on dwarf planet Ceres. Nature 2016. [DOI: 10.1038/nature.2016.20526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
33
|
Convection in a volatile nitrogen-ice-rich layer drives Pluto's geological vigour. Nature 2016; 534:82-5. [PMID: 27251279 DOI: 10.1038/nature18289] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 04/19/2016] [Indexed: 11/09/2022]
Abstract
The vast, deep, volatile-ice-filled basin informally named Sputnik Planum is central to Pluto's vigorous geological activity. Composed of molecular nitrogen, methane, and carbon monoxide ices, but dominated by nitrogen ice, this layer is organized into cells or polygons, typically about 10 to 40 kilometres across, that resemble the surface manifestation of solid-state convection. Here we report, on the basis of available rheological measurements, that solid layers of nitrogen ice with a thickness in excess of about one kilometre should undergo convection for estimated present-day heat-flow conditions on Pluto. More importantly, we show numerically that convective overturn in a several-kilometre-thick layer of solid nitrogen can explain the great lateral width of the cells. The temperature dependence of nitrogen-ice viscosity implies that the ice layer convects in the so-called sluggish lid regime, a unique convective mode not previously definitively observed in the Solar System. Average surface horizontal velocities of a few centimetres a year imply surface transport or renewal times of about 500,000 years, well under the ten-million-year upper-limit crater retention age for Sputnik Planum. Similar convective surface renewal may also occur on other dwarf planets in the Kuiper belt, which may help to explain the high albedos shown by some of these bodies.
Collapse
|
34
|
Weaver HA, Buie MW, Buratti BJ, Grundy WM, Lauer TR, Olkin CB, Parker AH, Porter SB, Showalter MR, Spencer JR, Stern SA, Verbiscer AJ, McKinnon WB, Moore JM, Robbins SJ, Schenk P, Singer KN, Barnouin OS, Cheng AF, Ernst CM, Lisse CM, Jennings DE, Lunsford AW, Reuter DC, Hamilton DP, Kaufmann DE, Ennico K, Young LA, Beyer RA, Binzel RP, Bray VJ, Chaikin AL, Cook JC, Cruikshank DP, Dalle Ore CM, Earle AM, Gladstone GR, Howett CJA, Linscott IR, Nimmo F, Parker JW, Philippe S, Protopapa S, Reitsema HJ, Schmitt B, Stryk T, Summers ME, Tsang CCC, Throop HHB, White OL, Zangari AM. The small satellites of Pluto as observed by New Horizons. Science 2016; 351:aae0030. [PMID: 26989256 DOI: 10.1126/science.aae0030] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The New Horizons mission has provided resolved measurements of Pluto's moons Styx, Nix, Kerberos, and Hydra. All four are small, with equivalent spherical diameters of ~40 kilometers for Nix and Hydra and ~10 kilometers for Styx and Kerberos. They are also highly elongated, with maximum to minimum axis ratios of ~2. All four moons have high albedos (~50 to 90%) suggestive of a water-ice surface composition. Crater densities on Nix and Hydra imply surface ages of at least 4 billion years. The small moons rotate much faster than synchronous, with rotational poles clustered nearly orthogonal to the common pole directions of Pluto and Charon. These results reinforce the hypothesis that the small moons formed in the aftermath of a collision that produced the Pluto-Charon binary.
Collapse
Affiliation(s)
- H A Weaver
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA.
| | - M W Buie
- Southwest Research Institute, Boulder, CO 80302, USA
| | - B J Buratti
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - W M Grundy
- Lowell Observatory, Flagstaff, AZ 86001, USA
| | - T R Lauer
- National Optical Astronomy Observatory, Tucson, AZ 26732, USA
| | - C B Olkin
- Southwest Research Institute, Boulder, CO 80302, USA
| | - A H Parker
- Southwest Research Institute, Boulder, CO 80302, USA
| | - S B Porter
- Southwest Research Institute, Boulder, CO 80302, USA
| | | | - J R Spencer
- Southwest Research Institute, Boulder, CO 80302, USA
| | - S A Stern
- 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, Washington University, St. Louis, MO 63130, USA
| | - J M Moore
- Space Science Division, NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - S J Robbins
- Southwest Research Institute, Boulder, CO 80302, USA
| | - P Schenk
- Lunar and Planetary Institute, Houston, TX 77058, USA
| | - K N Singer
- Southwest Research Institute, Boulder, CO 80302, USA
| | - O S Barnouin
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - A F Cheng
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - C M Ernst
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - C M Lisse
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, 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 C Reuter
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - D P Hamilton
- Department of Astronomy, University of Maryland, College Park, MD 20742, USA
| | - D E Kaufmann
- Southwest Research Institute, Boulder, CO 80302, USA
| | - K Ennico
- Space Science Division, NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - L A Young
- Southwest Research Institute, Boulder, CO 80302, USA
| | - R A Beyer
- SETI Institute, Mountain View, CA 94043, USA. Space Science Division, NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - R P Binzel
- Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - V J Bray
- University of Arizona, Tucson, AZ 85721, USA
| | - A L Chaikin
- Independent science writer, Arlington, VT, USA
| | - J C Cook
- Southwest Research Institute, Boulder, CO 80302, USA
| | - D P Cruikshank
- Space Science Division, NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - C M Dalle Ore
- Space Science Division, NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - A M Earle
- University of Arizona, Tucson, AZ 85721, USA
| | - G R Gladstone
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - C J A Howett
- Southwest Research Institute, Boulder, CO 80302, USA
| | | | - F Nimmo
- University of California, Santa Cruz, CA 95064, USA
| | - J Wm Parker
- Southwest Research Institute, Boulder, CO 80302, USA
| | - S Philippe
- Université Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France
| | - S Protopapa
- Department of Astronomy, University of Maryland, College Park, MD 20742, USA
| | - H J Reitsema
- Southwest Research Institute, Boulder, CO 80302, USA
| | - B Schmitt
- Université Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France
| | - T Stryk
- Roane State Community College, Oak Ridge, TN 37830, USA
| | - M E Summers
- George Mason University, Fairfax, VA 22030, USA
| | - C C C Tsang
- Southwest Research Institute, Boulder, CO 80302, USA
| | - H H B Throop
- Planetary Science Institute, Tucson, AZ 85719, USA
| | - O L White
- Space Science Division, NASA Ames Research Center, Moffett Field, CA 94035, USA
| | - A M Zangari
- Southwest Research Institute, Boulder, CO 80302, USA
| |
Collapse
|
35
|
Gladstone GR, Stern SA, Ennico K, Olkin CB, Weaver HA, Young LA, Summers ME, Strobel DF, Hinson DP, Kammer JA, Parker AH, Steffl AJ, Linscott IR, Parker JW, Cheng AF, Slater DC, Versteeg MH, Greathouse TK, Retherford KD, Throop H, Cunningham NJ, Woods WW, Singer KN, Tsang CCC, Schindhelm E, Lisse CM, Wong ML, Yung YL, Zhu X, Curdt W, Lavvas P, Young EF, Tyler GL, Bagenal F, Grundy WM, McKinnon WB, Moore JM, Spencer JR, Andert T, Andrews J, Banks M, Bauer B, Bauman J, Barnouin OS, Bedini P, Beisser K, Beyer RA, Bhaskaran S, Binzel RP, Birath E, Bird M, Bogan DJ, Bowman A, Bray VJ, Brozovic M, Bryan C, Buckley MR, Buie MW, Buratti BJ, Bushman SS, Calloway A, Carcich B, Conard S, Conrad CA, Cook JC, Cruikshank DP, Custodio OS, Ore CMD, Deboy C, Dischner ZJB, Dumont P, Earle AM, Elliott HA, Ercol J, Ernst CM, Finley T, Flanigan SH, Fountain G, Freeze MJ, Green JL, Guo Y, Hahn M, Hamilton DP, Hamilton SA, Hanley J, Harch A, Hart HM, Hersman CB, Hill A, Hill ME, Holdridge ME, Horanyi M, Howard AD, Howett CJA, Jackman C, Jacobson RA, Jennings DE, Kang HK, Kaufmann DE, Kollmann P, Krimigis SM, Kusnierkiewicz D, Lauer TR, Lee JE, Lindstrom KL, Lunsford AW, Mallder VA, Martin N, McComas DJ, McNutt RL, Mehoke D, Mehoke T, Melin ED, Mutchler M, Nelson D, Nimmo F, Nunez JI, Ocampo A, Owen WM, Paetzold M, Page B, Pelletier F, Peterson J, Pinkine N, Piquette M, Porter SB, Protopapa S, Redfern J, Reitsema HJ, Reuter DC, Roberts JH, Robbins SJ, Rogers G, Rose D, Runyon K, Ryschkewitsch MG, Schenk P, Sepan B, Showalter MR, Soluri M, Stanbridge D, Stryk T, Szalay JR, Tapley M, Taylor A, Taylor H, Umurhan OM, Verbiscer AJ, Versteeg MH, Vincent M, Webbert R, Weidner S, Weigle GE, White OL, Whittenburg K, Williams BG, Williams K, Williams S, Zangari AM, Zirnstein E. The atmosphere of Pluto as observed by New Horizons. Science 2016; 351:aad8866. [PMID: 26989258 DOI: 10.1126/science.aad8866] [Citation(s) in RCA: 179] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- G. Randall Gladstone
- Southwest Research Institute, San Antonio, TX 78238, USA
- University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - S. Alan Stern
- Southwest Research Institute, Boulder, CO 80302, USA
| | - Kimberly Ennico
- National Aeronautics and Space Administration, Ames Research Center, Space Science Division, Moffett Field, CA 94035, USA
| | | | - Harold A. Weaver
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | | | | | | | - David P. Hinson
- Search for Extraterrestrial Intelligence Institute, Mountain View, CA 94043, USA
| | | | | | | | | | | | - Andrew F. Cheng
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | | | | | | | - Kurt D. Retherford
- Southwest Research Institute, San Antonio, TX 78238, USA
- University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Henry Throop
- The Johns Hopkins University, Baltimore, MD 21218, USA
| | | | | | | | | | | | - Carey M. Lisse
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | | | - Yuk L. Yung
- California Institute of Technology, Pasadena, CA 91125, USA
| | - Xun Zhu
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - Werner Curdt
- Max-Planck-Institut für Sonnensystemforschung, 37191 Katlenburg-Lindau, Germany
| | - Panayotis Lavvas
- Groupe de Spectroscopie Moléculaire et Atmosphérique, Université Reims Champagne-Ardenne, 51687 Reims, France
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Weird and wonderful Pluto spills its secrets. Nature 2016. [DOI: 10.1038/nature.2016.19585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|