1
|
Kurth WS, Sulaiman AH, Hospodarsky GB, Menietti JD, Mauk BH, Clark G, Allegrini F, Valek P, Connerney JEP, Waite JH, Bolton SJ, Imai M, Santolik O, Li W, Duling S, Saur J, Louis C. Juno Plasma Wave Observations at Ganymede. Geophys Res Lett 2022; 49:e2022GL098591. [PMID: 37034392 PMCID: PMC10078157 DOI: 10.1029/2022gl098591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/22/2022] [Accepted: 04/27/2022] [Indexed: 06/19/2023]
Abstract
The Juno Waves instrument measured plasma waves associated with Ganymede's magnetosphere during its flyby on 7 June, day 158, 2021. Three distinct regions were identified including a wake, and nightside and dayside regions in the magnetosphere distinguished by their electron densities and associated variability. The magnetosphere includes electron cyclotron harmonic emissions including a band at the upper hybrid frequency, as well as whistler-mode chorus and hiss. These waves likely interact with energetic electrons in Ganymede's magnetosphere by pitch angle scattering and/or accelerating the electrons. The wake is accentuated by low-frequency turbulence and electrostatic solitary waves. Radio emissions observed before and after the flyby likely have their source in Ganymede's magnetosphere.
Collapse
Affiliation(s)
- W. S. Kurth
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | - A. H. Sulaiman
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | | | - J. D. Menietti
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | - B. H. Mauk
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - G. Clark
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - F. Allegrini
- Southwest Research InstituteSan AntonioTXUSA
- Department of Physics and AstronomyUniversity of Texas at San AntonioSan AntonioTXUSA
| | - P. Valek
- Southwest Research InstituteSan AntonioTXUSA
| | | | - J. H. Waite
- Southwest Research InstituteSan AntonioTXUSA
| | | | - M. Imai
- Department of Electrical Engineering and Information ScienceNational Institute of Technology (KOSEN), Niihama CollegeNiihamaJapan
| | - O. Santolik
- Department of Space PhysicsInstitute of Atmospheric Physics of the Czech Academy of SciencesPragueCzechia
- Faculty of Mathematics and PhysicsCharles UniversityPragueCzechia
| | - W. Li
- Center for Space PhysicsBoston UniversityBostonMAUSA
| | - S. Duling
- Institute of Geophysics and MeteorologyUniversity of CologneCologneGermany
| | - J. Saur
- Institute of Geophysics and MeteorologyUniversity of CologneCologneGermany
| | - C. Louis
- School of Cosmic Physics, DIAS Dunsink ObservatoryDublin Institute for Advanced StudiesDublinIreland
| |
Collapse
|
2
|
Bolton SJ, Levin SM, Guillot T, Li C, Kaspi Y, Orton G, Wong MH, Oyafuso F, Allison M, Arballo J, Atreya S, Becker HN, Bloxham J, Brown ST, Fletcher LN, Galanti E, Gulkis S, Janssen M, Ingersoll A, Lunine JL, Misra S, Steffes P, Stevenson D, Waite JH, Yadav RK, Zhang Z. Microwave observations reveal the deep extent and structure of Jupiter's atmospheric vortices. Science 2021; 374:968-972. [PMID: 34709937 DOI: 10.1126/science.abf1015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
Collapse
Affiliation(s)
- S J Bolton
- Southwest Research Institute, San Antonio, TX, USA
| | - S M Levin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - T Guillot
- Université Côte d'Azur, Observatoire de la Côte d'Azur, Centre National de la Recherche Scientifique, Laboratoire Lagrange, Nice, France
| | - C Li
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Y Kaspi
- Weizmann Institute of Science, Rehovot, 76100, Israel
| | - G Orton
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - M H Wong
- Carl Sagan Center for Research, SETI Institute, Mountain View, CA, USA
| | - F Oyafuso
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - M Allison
- Goddard Institute for Space Studies, New York, NY, USA.,Department of Astronomy, Columbia University, New York, NY 10027, USA
| | - J Arballo
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - S Atreya
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA
| | - H N Becker
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - J Bloxham
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
| | - S T Brown
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - L N Fletcher
- School of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK
| | - E Galanti
- Weizmann Institute of Science, Rehovot, 76100, Israel
| | - S Gulkis
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - M Janssen
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - A Ingersoll
- Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - J L Lunine
- Department of Astronomy, Cornell University, Ithaca, NY, USA
| | - S Misra
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - P Steffes
- Department of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - D Stevenson
- Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - J H Waite
- Southwest Research Institute, San Antonio, TX, USA
| | - R K Yadav
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Z Zhang
- Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| |
Collapse
|
3
|
Waite JH, Perryman RS, Perry ME, Miller KE, Bell J, Cravens TE, Glein CR, Grimes J, Hedman M, Cuzzi J, Brockwell T, Teolis B, Moore L, Mitchell DG, Persoon A, Kurth WS, Wahlund JE, Morooka M, Hadid LZ, Chocron S, Walker J, Nagy A, Yelle R, Ledvina S, Johnson R, Tseng W, Tucker OJ, Ip WH. Chemical interactions between Saturn’s atmosphere and its rings. Science 2018; 362:362/6410/eaat2382. [DOI: 10.1126/science.aat2382] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 09/10/2018] [Indexed: 11/03/2022]
Abstract
The Pioneer and Voyager spacecraft made close-up measurements of Saturn’s ionosphere and upper atmosphere in the 1970s and 1980s that suggested a chemical interaction between the rings and atmosphere. Exploring this interaction provides information on ring composition and the influence on Saturn’s atmosphere from infalling material. The Cassini Ion Neutral Mass Spectrometer sampled in situ the region between the D ring and Saturn during the spacecraft’s Grand Finale phase. We used these measurements to characterize the atmospheric structure and material influx from the rings. The atmospheric He/H2 ratio is 10 to 16%. Volatile compounds from the rings (methane; carbon monoxide and/or molecular nitrogen), as well as larger organic-bearing grains, are flowing inward at a rate of 4800 to 45,000 kilograms per second.
Collapse
|
4
|
Mitchell DG, Perry ME, Hamilton DC, Westlake JH, Kollmann P, Smith HT, Carbary JF, Waite JH, Perryman R, Hsu HW, Wahlund JE, Morooka MW, Hadid LZ, Persoon AM, Kurth WS. Dust grains fall from Saturn’s D-ring into its equatorial upper atmosphere. Science 2018; 362:362/6410/eaat2236. [DOI: 10.1126/science.aat2236] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 09/06/2018] [Indexed: 11/02/2022]
Abstract
The sizes of Saturn’s ring particles range from meters (boulders) to nanometers (dust). Determination of the rings’ ages depends on loss processes, including the transport of dust into Saturn’s atmosphere. During the Grand Finale orbits of the Cassini spacecraft, its instruments measured tiny dust grains that compose the innermost D-ring of Saturn. The nanometer-sized dust experiences collisions with exospheric (upper atmosphere) hydrogen and molecular hydrogen, which forces it to fall from the ring into the ionosphere and lower atmosphere. We used the Magnetospheric Imaging Instrument to detect and characterize this dust transport and also found that diffusion dominates above and near the altitude of peak ionospheric density. This mechanism results in a mass deposition into the equatorial atmosphere of ~5 kilograms per second, constraining the age of the D-ring.
Collapse
|
5
|
Mura A, Adriani A, Connerney JEP, Bolton S, Altieri F, Bagenal F, Bonfond B, Dinelli BM, Gérard JC, Greathouse T, Grodent D, Levin S, Mauk B, Moriconi ML, Saur J, Waite JH, Amoroso M, Cicchetti A, Fabiano F, Filacchione G, Grassi D, Migliorini A, Noschese R, Olivieri A, Piccioni G, Plainaki C, Sindoni G, Sordini R, Tosi F, Turrini D. Juno observations of spot structures and a split tail in Io-induced aurorae on Jupiter. Science 2018; 361:774-777. [PMID: 29976795 DOI: 10.1126/science.aat1450] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 06/15/2018] [Indexed: 11/02/2022]
Abstract
Jupiter's aurorae are produced in its upper atmosphere when incoming high-energy electrons precipitate along the planet's magnetic field lines. A northern and a southern main auroral oval are visible, surrounded by small emission features associated with the Galilean moons. We present infrared observations, obtained with the Juno spacecraft, showing that in the case of Io, this emission exhibits a swirling pattern that is similar in appearance to a von Kármán vortex street. Well downstream of the main auroral spots, the extended tail is split in two. Both of Ganymede's footprints also appear as a pair of emission features, which may provide a remote measure of Ganymede's magnetosphere. These features suggest that the magnetohydrodynamic interaction between Jupiter and its moon is more complex than previously anticipated.
Collapse
Affiliation(s)
- A Mura
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, Rome, Italy.
| | - A Adriani
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, Rome, Italy
| | - J E P Connerney
- Space Research Corporation, Annapolis, MD, USA.,NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - S Bolton
- Southwest Research Institute, San Antonio, TX, USA
| | - F Altieri
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, Rome, Italy
| | - F Bagenal
- Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, CO, USA
| | - B Bonfond
- Space Science, Technologies and Astrophysical Research Institute, Laboratory for Planetary and Atmospheric Physics, University of Liège, Liège, Belgium
| | - B M Dinelli
- Institute of Atmospheric Sciences and Climate, National Research Council, Italy
| | - J-C Gérard
- Space Science, Technologies and Astrophysical Research Institute, Laboratory for Planetary and Atmospheric Physics, University of Liège, Liège, Belgium
| | - T Greathouse
- Southwest Research Institute, San Antonio, TX, USA
| | - D Grodent
- Space Science, Technologies and Astrophysical Research Institute, Laboratory for Planetary and Atmospheric Physics, University of Liège, Liège, Belgium
| | - S Levin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - B Mauk
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD, USA
| | - M L Moriconi
- Institute of Atmospheric Sciences and Climate, National Research Council, Italy
| | - J Saur
- Institut für Geophysik und Meteorologie, University of Cologne, Köln, Germany
| | - J H Waite
- Southwest Research Institute, San Antonio, TX, USA.,Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
| | - M Amoroso
- Agenzia Spaziale Italiana, Rome, Italy
| | - A Cicchetti
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, Rome, Italy
| | - F Fabiano
- Institute of Atmospheric Sciences and Climate, National Research Council, Italy
| | - G Filacchione
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, Rome, Italy
| | - D Grassi
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, Rome, Italy
| | - A Migliorini
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, Rome, Italy
| | - R Noschese
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, Rome, Italy
| | | | - G Piccioni
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, Rome, Italy
| | - C Plainaki
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, Rome, Italy.,Agenzia Spaziale Italiana, Rome, Italy
| | - G Sindoni
- Agenzia Spaziale Italiana, Rome, Italy
| | - R Sordini
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, Rome, Italy
| | - F Tosi
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, Rome, Italy
| | - D Turrini
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, Rome, Italy
| |
Collapse
|
6
|
Abstract
Previous modeling studies of Titan's dayside ionosphere predict electron number densities that are roughly a factor of 2 higher than those observed by the RPWS/Langmuir probe. The issue can equivalently be described as the ratio between the calculated electron production rates and the square of the observed electron number densities resulting in roughly a factor of 4 higher effective recombination coefficient than expected from the ion composition and the electron temperature. Here we make an extended reassessment of Titan's dayside ionization balance, focusing on 34 flybys between TA and T120. Using a recalibrated data set and by taking the presence of negative ions into account, we arrive at lower effective recombination coefficients compared with earlier studies. The values are still higher than expected from the ion composition and the electron temperature, but by a factor of ~2-3 instead of a factor of ~4. We have also investigated whether the derived effective recombination coefficients display dependencies on the solar zenith angle (SZA), the integrated solar EUV intensity (<80 nm), and the corotational plasma ram direction (RAM), and found statistically significant trends, which may be explained by a declining photoionization against the background ionization by magnetospheric particles (trends in SZA and RAM) and altered photochemistry (trend in EUV). We find that a series of flybys that occurred during solar minimum (2008) and with similar flyby geometries are associated with enhanced values of the effective recombination coefficient compared with the remaining data set, which also suggests a chemistry dependence on the sunlight conditions.
Collapse
Affiliation(s)
- O Shebanits
- Swedish Institute of Space Physics, Uppsala, Sweden
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - E Vigren
- Swedish Institute of Space Physics, Uppsala, Sweden
| | - J-E Wahlund
- Swedish Institute of Space Physics, Uppsala, Sweden
| | - N J T Edberg
- Swedish Institute of Space Physics, Uppsala, Sweden
| | - J Cui
- School of Atmospheric Sciences, Sun Yat-Sen University, Zhuhai, Guangdong, China
| | - K E Mandt
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, TX, USA
| | - J H Waite
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, TX, USA
| |
Collapse
|
7
|
Shebanits O, Vigren E, Wahlund JE, Holmberg MKG, Morooka M, Edberg NJT, Mandt KE, Waite JH. Titan's ionosphere: A survey of solar EUV influences. J Geophys Res Space Phys 2017; 122:7491-7503. [PMID: 31106105 PMCID: PMC6525010 DOI: 10.1002/2017ja023987] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Effects of solar EUV on positive ions and heavy negative charge carriers (molecular ions, aerosol, and/or dust) in Titan's ionosphere are studied over the course of almost 12 years, including 78 flybys below 1400 km altitude between TA (October 2004) and T120 (June 2016). The Radio and Plasma Wave Science/Langmuir Probe-measured ion charge densities (normalized by the solar zenith angle) show statistically significant variations with respect to the solar EUV flux. Dayside charge densities increase by a factor of ≈2 from solar minimum to maximum, while nightside charge densities are found to anticorrelate with the EUV flux and decrease by a factor of ≈3-4. The overall EUV dependence of the ion charge densities suggest inapplicability of the idealized Chapman theory below 1200 km in Titan's ionosphere. Nightside charge densities are also found to vary along Titan's orbit, with higher values in the sunward magnetosphere of Saturn compared to the magnetotail.
Collapse
Affiliation(s)
- O. Shebanits
- Swedish Institute of Space Physics, Uppsala, Sweden
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - E. Vigren
- Swedish Institute of Space Physics, Uppsala, Sweden
| | | | - M. K. G. Holmberg
- Université de Toulouse, UPS-OMP, IRAP, Toulouse, France
- CNRS, IRAP, Toulouse, France
| | - M. Morooka
- Swedish Institute of Space Physics, Uppsala, Sweden
| | | | - K. E. Mandt
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, Texas, USA
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, Texas, USA
| | - J. H. Waite
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, Texas, USA
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, Texas, USA
| |
Collapse
|
8
|
Marty B, Altwegg K, Balsiger H, Bar-Nun A, Bekaert DV, Berthelier JJ, Bieler A, Briois C, Calmonte U, Combi M, De Keyser J, Fiethe B, Fuselier SA, Gasc S, Gombosi TI, Hansen KC, Hässig M, Jäckel A, Kopp E, Korth A, Le Roy L, Mall U, Mousis O, Owen T, Rème H, Rubin M, Sémon T, Tzou CY, Waite JH, Wurz P. Xenon isotopes in 67P/Churyumov-Gerasimenko show that comets contributed to Earth's atmosphere. Science 2017; 356:1069-1072. [DOI: 10.1126/science.aal3496] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 05/03/2017] [Indexed: 11/02/2022]
Affiliation(s)
- B. Marty
- Centre de Recherches Pétrographiques et Géochimiques, CNRS, Université de Lorraine, 15 rue Notre Dame des Pauvres, BP 20, 54501 Vandoeuvre lès Nancy, France
| | - K. Altwegg
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
- Center for Space and Habitability, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - H. Balsiger
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - A. Bar-Nun
- Department of Geoscience, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - D. V. Bekaert
- Centre de Recherches Pétrographiques et Géochimiques, CNRS, Université de Lorraine, 15 rue Notre Dame des Pauvres, BP 20, 54501 Vandoeuvre lès Nancy, France
| | - J.-J. Berthelier
- Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Institut Pierre Simon Laplace, CNRS, Université Pierre et Marie Curie, 4 Avenue de Neptune, 94100 Saint-Maur, France
| | - A. Bieler
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
- Department of Climate and Space Sciences and Engineering, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109, USA
| | - C. Briois
- Laboratoire de Physique et Chimie de l’Environnement et de l’Espace (LPC2E), UMR 6115 CNRS–Université d’Orléans, France
| | - U. Calmonte
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - M. Combi
- Department of Climate and Space Sciences and Engineering, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109, USA
| | - J. De Keyser
- Koninklijk Belgisch Instituut voor Ruimte-Aeronomie/Institut Royal d’Aéronomie Spatiale de Belgique (BIRA-IASB), Ringlaan 3, B-1180 Brussels, Belgium
| | - B. Fiethe
- Institute of Computer and Network Engineering (IDA), Technische Universität Braunschweig, Hans-Sommer-Straße 66, D-38106 Braunschweig, Germany
| | - S. A. Fuselier
- Department of Space Science, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228, USA
| | - S. Gasc
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - T. I. Gombosi
- Department of Climate and Space Sciences and Engineering, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109, USA
| | - K. C. Hansen
- Department of Climate and Space Sciences and Engineering, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109, USA
| | - M. Hässig
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
- Department of Space Science, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228, USA
| | - A. Jäckel
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - E. Kopp
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - A. Korth
- Max-Planck-Institut für Sonnensystemforschung (MPS), Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
| | - L. Le Roy
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - U. Mall
- Max-Planck-Institut für Sonnensystemforschung (MPS), Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
| | - O. Mousis
- Laboratoire d’Astrophysique de Marseille, CNRS, Aix Marseille Université, 13388 Marseille, France
| | - T. Owen
- Institute for Astronomy, University of Hawaii, Honolulu, HI 96822, USA
| | - H. Rème
- Institut de Recherche en Astrophysique et Planétologie, CNRS, Université Paul Sabatier, Observatoire Midi-Pyrénées, 9 Avenue du Colonel Roche, 31028 Toulouse Cedex 4, France
| | - M. Rubin
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - T. Sémon
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - C.-Y. Tzou
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - J. H. Waite
- Department of Space Science, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228, USA
| | - P. Wurz
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| |
Collapse
|
9
|
Shebanits O, Wahlund JE, Edberg NJT, Crary FJ, Wellbrock A, Andrews DJ, Vigren E, Desai RT, Coates AJ, Mandt KE, Waite JH. Ion and aerosol precursor densities in Titan's ionosphere: A multi-instrument case study. J Geophys Res Space Phys 2016; 121:10075-10090. [PMID: 31106104 PMCID: PMC6525009 DOI: 10.1002/2016ja022980] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The importance of the heavy ions and dust grains for the chemistry and aerosol formation in Titan's ionosphere has been well established in the recent years of the Cassini mission. In this study we combine independent in situ plasma (Radio Plasma and Wave Science Langmuir Probe (RPWS/LP)) and particle (Cassini Plasma Science Electron Spectrometer, Cassini Plasma Science Ion Beam Spectrometer, and Ion and Neutral Mass Spectrometer) measurements of Titan's ionosphere for selected flybys (T16, T29, T40, and T56) to produce altitude profiles of mean ion masses including heavy ions and develop a Titan-specific method for detailed analysis of the RPWS/LP measurements (applicable to all flybys) to further constrain ion charge densities and produce the first empirical estimate of the average charge of negative ions and/or dust grains. Our results reveal the presence of an ion-ion (dusty) plasma below ~1100 km altitude, with charge densities exceeding the primary ionization peak densities by a factor ≥2 in the terminator and nightside ionosphere (n e /n i ≤ 0.1). We suggest that ion-ion (dusty) plasma may also be present in the dayside ionosphere below 900 km (n e /n i < 0.5 at 1000 km altitude). The average charge of the dust grains (≥1000 amu) is estimated to be between -2.5 and -1.5 elementary charges, increasing toward lower altitudes.
Collapse
Affiliation(s)
- O. Shebanits
- Swedish Institute of Space Physics, Uppsala, Sweden
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | | | | | - F. J. Crary
- University of Colorado Boulder, Boulder, Colorado, USA
| | - A. Wellbrock
- Mullard Space Science Laboratory, University College London, London, UK
- Centre for Planetary Sciences, University College London/Birkbeck, London, UK
| | | | - E. Vigren
- Swedish Institute of Space Physics, Uppsala, Sweden
| | - R. T. Desai
- Mullard Space Science Laboratory, University College London, London, UK
- Centre for Planetary Sciences, University College London/Birkbeck, London, UK
| | - A. J. Coates
- Mullard Space Science Laboratory, University College London, London, UK
- Centre for Planetary Sciences, University College London/Birkbeck, London, UK
| | - K. E. Mandt
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, Texas, USA
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, Texas, USA
| | - J. H. Waite
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, Texas, USA
| |
Collapse
|
10
|
Holm NG, Oze C, Mousis O, Waite JH, Guilbert-Lepoutre A. Serpentinization and the Formation of H2 and CH4 on Celestial Bodies (Planets, Moons, Comets). Astrobiology 2015; 15:587-600. [PMID: 26154779 PMCID: PMC4523005 DOI: 10.1089/ast.2014.1188] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 01/28/2015] [Indexed: 05/22/2023]
Abstract
Serpentinization involves the hydrolysis and transformation of primary ferromagnesian minerals such as olivine ((Mg,Fe)2SiO4) and pyroxenes ((Mg,Fe)SiO3) to produce H2-rich fluids and a variety of secondary minerals over a wide range of environmental conditions. The continual and elevated production of H2 is capable of reducing carbon, thus initiating an inorganic pathway to produce organic compounds. The production of H2 and H2-dependent CH4 in serpentinization systems has received significant interdisciplinary interest, especially with regard to the abiotic synthesis of organic compounds and the origins and maintenance of life in Earth's lithosphere and elsewhere in the Universe. Here, serpentinization with an emphasis on the formation of H2 and CH4 are reviewed within the context of the mineralogy, temperature/pressure, and fluid/gas chemistry present in planetary environments. Whether deep in Earth's interior or in Kuiper Belt Objects in space, serpentinization is a feasible process to invoke as a means of producing astrobiologically indispensable H2 capable of reducing carbon to organic compounds.
Collapse
Affiliation(s)
- N G Holm
- 1 Department of Geological Sciences, Stockholm University , Stockholm, Sweden
| | - C Oze
- 2 Department of Geological Sciences, University of Canterbury , Christchurch, New Zealand
| | - O Mousis
- 3 Aix Marseille Université , CNRS, LAM (Laboratoire d'Astrophysique de Marseille) UMR 7326, Marseille, France
| | - J H Waite
- 4 Space Science and Engineering Division, Southwest Research Institute , San Antonio, Texas, USA
| | | |
Collapse
|
11
|
Rubin M, Altwegg K, Balsiger H, Bar-Nun A, Berthelier JJ, Bieler A, Bochsler P, Briois C, Calmonte U, Combi M, De Keyser J, Dhooghe F, Eberhardt P, Fiethe B, Fuselier SA, Gasc S, Gombosi TI, Hansen KC, Hässig M, Jäckel A, Kopp E, Korth A, Le Roy L, Mall U, Marty B, Mousis O, Owen T, Rème H, Sémon T, Tzou CY, Waite JH, Wurz P. Molecular nitrogen in comet 67P/Churyumov-Gerasimenko indicates a low formation temperature. Science 2015; 348:232-5. [PMID: 25791084 DOI: 10.1126/science.aaa6100] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 03/03/2015] [Indexed: 11/02/2022]
Abstract
Molecular nitrogen (N2) is thought to have been the most abundant form of nitrogen in the protosolar nebula. It is the main N-bearing molecule in the atmospheres of Pluto and Triton and probably the main nitrogen reservoir from which the giant planets formed. Yet in comets, often considered the most primitive bodies in the solar system, N2 has not been detected. Here we report the direct in situ measurement of N2 in the Jupiter family comet 67P/Churyumov-Gerasimenko, made by the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis mass spectrometer aboard the Rosetta spacecraft. A N2/CO ratio of (5.70 ± 0.66) × 10(-3) (2σ standard deviation of the sampled mean) corresponds to depletion by a factor of ~25.4 ± 8.9 as compared to the protosolar value. This depletion suggests that cometary grains formed at low-temperature conditions below ~30 kelvin.
Collapse
Affiliation(s)
- M Rubin
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland.
| | - K Altwegg
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland. Center for Space and Habitability, University of Bern, Sidlerstrasse. 5, CH-3012 Bern, Switzerland
| | - H Balsiger
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - A Bar-Nun
- Department of Geoscience, Tel-Aviv University, Ramat-Aviv, Tel-Aviv, Israel
| | - J-J Berthelier
- Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS)/Institute Pierre Simon Laplace-CNRS-UPMC-UVSQ, 4 Avenue de Neptune F-94100, Saint-Maur, France
| | - A Bieler
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland. Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward, Ann Arbor, MI 48109, USA
| | - P Bochsler
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - C Briois
- Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), UMR 6115 CNRS-Université d'Orléans, Orléans, France
| | - U Calmonte
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - M Combi
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward, Ann Arbor, MI 48109, USA
| | - J De Keyser
- Belgian Institute for Space Aeronomy, Belgisch Instituut voor Ruimte-Aeronomie-Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Ringlaan 3, B-1180 Brussels, Belgium
| | - F Dhooghe
- Belgian Institute for Space Aeronomy, Belgisch Instituut voor Ruimte-Aeronomie-Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Ringlaan 3, B-1180 Brussels, Belgium
| | - P Eberhardt
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - B Fiethe
- Institute of Computer and Network Engineering, Technische Universität Braunschweig, Hans-Sommer-Straße 66, D-38106 Braunschweig, Germany
| | - S A Fuselier
- Department of Space Science, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228, USA
| | - S Gasc
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - T I Gombosi
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward, Ann Arbor, MI 48109, USA
| | - K C Hansen
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward, Ann Arbor, MI 48109, USA
| | - M Hässig
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland. Department of Space Science, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228, USA
| | - A Jäckel
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - E Kopp
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - A Korth
- Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
| | - L Le Roy
- Center for Space and Habitability, University of Bern, Sidlerstrasse. 5, CH-3012 Bern, Switzerland
| | - U Mall
- Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
| | - B Marty
- Centre de Recherches Pétrographiques et Géochimiques (CRPG)-CNRS, Université de Lorraine, 15 rue Notre Dame des Pauvres, Bôite Postale 20, 54501 Vandoeuvre lès Nancy, France
| | - O Mousis
- Aix Marseille Université, CNRS, Laboratoire d'Astrophysique de Marseille UMR 7326, 13388, Marseille, France
| | - T Owen
- Institute for Astronomy, University of Hawaii, Honolulu, HI 96822, USA
| | - H Rème
- Université de Toulouse; UPS-OMP; Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France. CNRS; IRAP; 9 Avenue du Colonel Roche, Boîte Postale 44346, F-31028 Toulouse Cedex 4, France
| | - T Sémon
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - C-Y Tzou
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - J H Waite
- Department of Space Science, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228, USA
| | - P Wurz
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| |
Collapse
|
12
|
Hässig M, Altwegg K, Balsiger H, Bar-Nun A, Berthelier JJ, Bieler A, Bochsler P, Briois C, Calmonte U, Combi M, De Keyser J, Eberhardt P, Fiethe B, Fuselier SA, Galand M, Gasc S, Gombosi TI, Hansen KC, Jäckel A, Keller HU, Kopp E, Korth A, Kührt E, Le Roy L, Mall U, Marty B, Mousis O, Neefs E, Owen T, Rème H, Rubin M, Sémon T, Tornow C, Tzou CY, Waite JH, Wurz P. Cometary science. Time variability and heterogeneity in the coma of 67P/Churyumov-Gerasimenko. Science 2015; 347:aaa0276. [PMID: 25613892 DOI: 10.1126/science.aaa0276] [Citation(s) in RCA: 204] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Comets contain the best-preserved material from the beginning of our planetary system. Their nuclei and comae composition reveal clues about physical and chemical conditions during the early solar system when comets formed. ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) onboard the Rosetta spacecraft has measured the coma composition of comet 67P/Churyumov-Gerasimenko with well-sampled time resolution per rotation. Measurements were made over many comet rotation periods and a wide range of latitudes. These measurements show large fluctuations in composition in a heterogeneous coma that has diurnal and possibly seasonal variations in the major outgassing species: water, carbon monoxide, and carbon dioxide. These results indicate a complex coma-nucleus relationship where seasonal variations may be driven by temperature differences just below the comet surface.
Collapse
Affiliation(s)
- M Hässig
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland. Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA.
| | - K Altwegg
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland. Center for Space and Habitability (CSH), University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - H Balsiger
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - A Bar-Nun
- Department of Geosciences, Tel-Aviv University, Ramat-Aviv, Tel-Aviv, Israel
| | - J J Berthelier
- Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Institute Pierre Simon Laplace (IPSL), Centre national de recherche scientifique (CNRS), Université Pierre et Marie Curie (UPMC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), BP 102, UPMC, 4 Place Jussieu, F-75252 Paris Cedex 05, France
| | - A Bieler
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland. Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109, USA
| | - P Bochsler
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - C Briois
- Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), UMR 7328 CNRS - Université d'Orléans, France
| | - U Calmonte
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - M Combi
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109, USA
| | - J De Keyser
- Belgian Institute for Space Aeronomy (BIRA-IASB), Ringlaan 3, B-1180 Brussels, Belgium. Center for Plasma Astrophysics, KULeuven, Celestijnenlaan 200D, 3001 Heverlee, Belgium
| | - P Eberhardt
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - B Fiethe
- Institute of Computer and Network Engineering (IDA), TU Braunschweig, Hans-Sommer-Straße 66, D-38106 Braunschweig, Germany
| | - S A Fuselier
- Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA
| | - M Galand
- Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK
| | - S Gasc
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - T I Gombosi
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109, USA
| | - K C Hansen
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109, USA
| | - A Jäckel
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - H U Keller
- Institute for Geophysics and Extraterrestrial Physics, Technische Universität (TU) Braunschweig, 38106 Braunschweig, Germany. German Aerospace Center, Institute of Planetary Research, Asteroids and Comets, Rutherfordstraße 2, 12489 Berlin, Germany
| | - E Kopp
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - A Korth
- Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
| | - E Kührt
- German Aerospace Center, Institute of Planetary Research, Asteroids and Comets, Rutherfordstraße 2, 12489 Berlin, Germany
| | - L Le Roy
- Center for Space and Habitability (CSH), University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - U Mall
- Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
| | - B Marty
- Centre de Recherches Pétrographiques et Géochimiques (CRPG), 15 Rue Notre Dame des Pauvres, BP 20, 54501 Vandoeuvre lès Nancy, France
| | - O Mousis
- Aix Marseille Université, CNRS, LAM (Laboratoire d'Astrophysique de Marseille), UMR 7326, 13388, Marseille, France
| | - E Neefs
- Engineering Division, BIRA-IASB, Ringlaan 3, B-1180 Brussels, Belgium
| | - T Owen
- Institute for Astronomy, University of Hawaii, Honolulu, HI 96822, USA
| | - H Rème
- Université de Toulouse, Université Paul Sabathier (UPS), Observatoire de Midi-Pyrénées (OMP), Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France. CNRS, IRAP, 9 Avenue du Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4, France
| | - M Rubin
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - T Sémon
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - C Tornow
- German Aerospace Center, Institute of Planetary Research, Asteroids and Comets, Rutherfordstraße 2, 12489 Berlin, Germany
| | - C-Y Tzou
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - J H Waite
- Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA
| | - P Wurz
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| |
Collapse
|
13
|
Teolis BD, Sillanpää I, Waite JH, Khurana KK. Surface current balance and thermoelectric whistler wings at airless astrophysical bodies: Cassini at Rhea. J Geophys Res Space Phys 2014; 119:8881-8901. [PMID: 26167436 PMCID: PMC4497460 DOI: 10.1002/2014ja020094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 10/02/2014] [Accepted: 10/04/2014] [Indexed: 06/04/2023]
Abstract
UNLABELLED Sharp magnetic perturbations found by the Cassini spacecraft at the edge of the Rhea flux tube are consistent with field-aligned flux tube currents. The current system results from the difference of ion and electron gyroradii and the requirement to balance currents on the sharp Rhea surface. Differential-type hybrid codes that solve for ion velocity and magnetic field have an intrinsic difficulty modeling the plasma absorber's sharp surface. We overcome this problem by instead using integral equations to solve for ion and electron currents and obtain agreement with the magnetic perturbations at Rhea's flux tube edge. An analysis of the plasma dispersion relations and Cassini data reveals that field-guided whistler waves initiated by (1) the electron velocity anisotropy in the flux tube and (2) interaction with surface sheath electrostatic waves on topographic scales may facilitate propagation of the current system to large distances from Rhea. Current systems like those at Rhea should occur generally, for plasma absorbers of any size such as spacecraft or planetary bodies, in a wide range of space plasma environments. Motion through the plasma is not essential since the current system is thermodynamic in origin, excited by heat flow into the object. The requirements are a difference of ion and electron gyroradii and a sharp surface, i.e., without a significant thick atmosphere. KEY POINTS Surface current balance condition yields a current system at astronomical bodiesCurrent system possible for sharp (airless) objects of any sizeCurrent system is thermoelectric and motion through the plasma nonessential.
Collapse
Affiliation(s)
- B D Teolis
- Space Science Division, Southwest Research Institute San Antonio, Texas, USA
| | - I Sillanpää
- Space Science Division, Southwest Research Institute San Antonio, Texas, USA
| | - J H Waite
- Space Science Division, Southwest Research Institute San Antonio, Texas, USA
| | - K K Khurana
- Institute of Geophysics and Planetary Physics, University of California Los Angeles, California, USA
| |
Collapse
|
14
|
Nordheim TA, Jones GH, Roussos E, Leisner JS, Coates AJ, Kurth WS, Khurana KK, Krupp N, Dougherty MK, Waite JH. Detection of a strongly negative surface potential at Saturn's moon Hyperion. Geophys Res Lett 2014; 41:7011-7018. [PMID: 26074639 PMCID: PMC4459206 DOI: 10.1002/2014gl061127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 09/11/2014] [Indexed: 06/04/2023]
Abstract
On 26 September 2005, Cassini conducted its only close targeted flyby of Saturn's small, irregularly shaped moon Hyperion. Approximately 6 min before the closest approach, the electron spectrometer (ELS), part of the Cassini Plasma Spectrometer (CAPS) detected a field-aligned electron population originating from the direction of the moon's surface. Plasma wave activity detected by the Radio and Plasma Wave instrument suggests electron beam activity. A dropout in energetic electrons was observed by both CAPS-ELS and the Magnetospheric Imaging Instrument Low-Energy Magnetospheric Measurement System, indicating that the moon and the spacecraft were magnetically connected when the field-aligned electron population was observed. We show that this constitutes a remote detection of a strongly negative (∼ -200 V) surface potential on Hyperion, consistent with the predicted surface potential in regions near the solar terminator.
Collapse
Affiliation(s)
- T A Nordheim
- Mullard Space Science Laboratory, University College LondonDorking, UK
- Centre for Planetary Sciences at UCL/BirkbeckLondon, UK
| | - G H Jones
- Mullard Space Science Laboratory, University College LondonDorking, UK
- Centre for Planetary Sciences at UCL/BirkbeckLondon, UK
| | - E Roussos
- Max Planck Institute for Solar System ResearchGöttingen, Germany
| | - J S Leisner
- Institute for Theoretical Physics, Braunschweig University of TechnologyBraunschweig, Germany
- Now at SDSE, LLCSilver Spring, Maryland, USA
| | - A J Coates
- Mullard Space Science Laboratory, University College LondonDorking, UK
- Centre for Planetary Sciences at UCL/BirkbeckLondon, UK
| | - W S Kurth
- Department of Physics and Astronomy, University of IowaIowa City, Iowa, USA
| | - K K Khurana
- Institute of Geophysics and Planetary Physics, University of CaliforniaLos Angeles, California, USA
| | - N Krupp
- Max Planck Institute for Solar System ResearchGöttingen, Germany
| | - M K Dougherty
- Blackett Laboratory, Imperial College LondonLondon, UK
| | - J H Waite
- Southwest Research InstituteSan Antonio, Texas, USA
| |
Collapse
|
15
|
Jasinski JM, Arridge CS, Lamy L, Leisner JS, Thomsen MF, Mitchell DG, Coates AJ, Radioti A, Jones GH, Roussos E, Krupp N, Grodent D, Dougherty MK, Waite JH. Cusp observation at Saturn's high-latitude magnetosphere by the Cassini spacecraft. Geophys Res Lett 2014; 41:1382-1388. [PMID: 25821276 PMCID: PMC4373149 DOI: 10.1002/2014gl059319] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 02/13/2014] [Indexed: 05/24/2023]
Abstract
UNLABELLED We report on the first analysis of magnetospheric cusp observations at Saturn by multiple in situ instruments onboard the Cassini spacecraft. Using this we infer the process of reconnection was occurring at Saturn's magnetopause. This agrees with remote observations that showed the associated auroral signatures of reconnection. Cassini crossed the northern cusp around noon local time along a poleward trajectory. The spacecraft observed ion energy-latitude dispersions-a characteristic signature of the terrestrial cusp. This ion dispersion is "stepped," which shows that the reconnection is pulsed. The ion energy-pitch angle dispersions suggest that the field-aligned distance from the cusp to the reconnection site varies between ∼27 and 51 RS . An intensification of lower frequencies of the Saturn kilometric radiation emissions suggests the prior arrival of a solar wind shock front, compressing the magnetosphere and providing more favorable conditions for magnetopause reconnection. KEY POINTS We observe evidence for reconnection in the cusp plasma at SaturnWe present evidence that the reconnection process can be pulsed at SaturnSaturn's cusp shows similar characteristics to the terrestrial cusp.
Collapse
Affiliation(s)
- J M Jasinski
- Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London Dorking, Surrey, UK ; Centre for Planetary Sciences, UCL/Birkbeck London, UK
| | - C S Arridge
- Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London Dorking, Surrey, UK ; Centre for Planetary Sciences, UCL/Birkbeck London, UK
| | - L Lamy
- LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris 6, Université Paris Diderot Meudon, France
| | - J S Leisner
- Blackett Laboratory, Department of Physics, Imperial College London London, UK
| | - M F Thomsen
- Planetary Science Institute Tucson, Arizona, USA
| | - D G Mitchell
- Applied Physics Laboratory, Johns Hopkins University Laurel, Maryland, USA
| | - A J Coates
- Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London Dorking, Surrey, UK ; Centre for Planetary Sciences, UCL/Birkbeck London, UK
| | - A Radioti
- Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique, Université de Liége Liege, Belgium
| | - G H Jones
- Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London Dorking, Surrey, UK ; Centre for Planetary Sciences, UCL/Birkbeck London, UK
| | - E Roussos
- Max-Planck-Institut für Sonnensystemforschung Göttingen, Germany
| | - N Krupp
- Max-Planck-Institut für Sonnensystemforschung Göttingen, Germany
| | - D Grodent
- Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique, Université de Liége Liege, Belgium
| | | | - J H Waite
- Southwest Research Institute, Space Science and Engineering Division San Antonio, Texas, USA
| |
Collapse
|
16
|
|
17
|
Westlake JH, Waite JH, Mandt KE, Carrasco N, Bell JM, Magee BA, Wahlund JE. Titan's ionospheric composition and structure: Photochemical modeling of Cassini INMS data. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011je003883] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
18
|
Affiliation(s)
- Y. Dong
- Physics and Astronomy Department; Rice University; Houston Texas USA
| | - T. W. Hill
- Physics and Astronomy Department; Rice University; Houston Texas USA
| | - B. D. Teolis
- Space Science and Engineering Division; Southwest Research Institute; San Antonio Texas USA
| | - B. A. Magee
- Space Science and Engineering Division; Southwest Research Institute; San Antonio Texas USA
| | - J. H. Waite
- Space Science and Engineering Division; Southwest Research Institute; San Antonio Texas USA
| |
Collapse
|
19
|
Richard MS, Cravens TE, Robertson IP, Waite JH, Wahlund JE, Crary FJ, Coates AJ. Energetics of Titan's ionosphere: Model comparisons with Cassini data. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016603] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- M. S. Richard
- Department of Physics and Astronomy; University of Kansas; Lawrence Kansas USA
| | - T. E. Cravens
- Department of Physics and Astronomy; University of Kansas; Lawrence Kansas USA
| | - I. P. Robertson
- Department of Physics and Astronomy; University of Kansas; Lawrence Kansas USA
| | - J. H. Waite
- Southwest Research Institute; San Antonio Texas USA
| | | | - F. J. Crary
- Southwest Research Institute; San Antonio Texas USA
| | - A. J. Coates
- Mullard Space Science Laboratory, Holmbury St. Mary; University College London; Dorking, Surrey UK
| |
Collapse
|
20
|
Westlake JH, Bell JM, Waite JH, Johnson RE, Luhmann JG, Mandt KE, Magee BA, Rymer AM. Titan's thermospheric response to various plasma environments. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010ja016251] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- J. H. Westlake
- Department of Physics and Astronomy; University of Texas at San Antonio; San Antonio Texas USA
| | - J. M. Bell
- Space Science and Engineering Division; Southwest Research Institute; San Antonio Texas USA
| | - J. H. Waite
- Department of Physics and Astronomy; University of Texas at San Antonio; San Antonio Texas USA
- Space Science and Engineering Division; Southwest Research Institute; San Antonio Texas USA
| | - R. E. Johnson
- Engineering Physics Program; University of Virginia; Charlottesville Virginia USA
| | - J. G. Luhmann
- Space Sciences Laboratory; University of California; Berkeley California USA
| | - K. E. Mandt
- Space Science and Engineering Division; Southwest Research Institute; San Antonio Texas USA
- Department of Environmental and Civil Engineering; University of Texas at San Antonio; San Antonio Texas USA
| | - B. A. Magee
- Space Science and Engineering Division; Southwest Research Institute; San Antonio Texas USA
| | - A. M. Rymer
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| |
Collapse
|
21
|
Teolis BD, Jones GH, Miles PF, Tokar RL, Magee BA, Waite JH, Roussos E, Young DT, Crary FJ, Coates AJ, Johnson RE, Tseng WL, Baragiola RA. Cassini Finds an Oxygen-Carbon Dioxide Atmosphere at Saturn's Icy Moon Rhea. Science 2010; 330:1813-5. [DOI: 10.1126/science.1198366] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
22
|
Teolis BD, Perry ME, Magee BA, Westlake J, Waite JH. Detection and measurement of ice grains and gas distribution in the Enceladus plume by Cassini's Ion Neutral Mass Spectrometer. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009ja015192] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- B. D. Teolis
- Southwest Research Institute, Space Science and Engineering Division; San Antonio Texas USA
| | - M. E. Perry
- Johns Hopkins University, Applied Physics Laboratory; Laurel Maryland USA
| | - B. A. Magee
- Southwest Research Institute, Space Science and Engineering Division; San Antonio Texas USA
| | - J. Westlake
- Southwest Research Institute, Space Science and Engineering Division; San Antonio Texas USA
| | - J. H. Waite
- Southwest Research Institute, Space Science and Engineering Division; San Antonio Texas USA
| |
Collapse
|
23
|
Cravens TE, Richard M, Ma YJ, Bertucci C, Luhmann JG, Ledvina S, Robertson IP, Wahlund JE, Ågren K, Cui J, Muller-Wodarg I, Waite JH, Dougherty M, Bell J, Ulusen D. Dynamical and magnetic field time constants for Titan's ionosphere: Empirical estimates and comparisons with Venus. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009ja015050] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- T. E. Cravens
- Department of Physics and Astronomy; University of Kansas; Lawrence Kansas USA
| | - M. Richard
- Department of Physics and Astronomy; University of Kansas; Lawrence Kansas USA
| | - Y.-J. Ma
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
| | - C. Bertucci
- Instituto de Astronomía y Física del Espacio; Buenos Aires Argentina
| | - J. G. Luhmann
- Space Sciences Laboratory; University of California; Berkeley California USA
| | - S. Ledvina
- Space Sciences Laboratory; University of California; Berkeley California USA
| | - I. P. Robertson
- Department of Physics and Astronomy; University of Kansas; Lawrence Kansas USA
| | | | - K. Ågren
- Swedish Institute of Space Physics; Uppsala Sweden
| | - J. Cui
- Space and Atmospheric Physics Group, Blackett Laboratory; Imperial College London; London UK
| | - I. Muller-Wodarg
- Space and Atmospheric Physics Group, Blackett Laboratory; Imperial College London; London UK
| | - J. H. Waite
- Southwest Research Institute; San Antonio Texas USA
| | - M. Dougherty
- Space and Atmospheric Physics Group, Blackett Laboratory; Imperial College London; London UK
| | - J. Bell
- Southwest Research Institute; San Antonio Texas USA
| | - D. Ulusen
- Space Sciences Laboratory; University of California; Berkeley California USA
| |
Collapse
|
24
|
Affiliation(s)
- J. Cui
- Space and Atmospheric Physics Group, Department of Physics; Imperial College London; London UK
| | - M. Galand
- Space and Atmospheric Physics Group, Department of Physics; Imperial College London; London UK
| | - R. V. Yelle
- Lunar and Planetary Laboratory; University of Arizona; Tucson Arizona USA
| | | | - K. Ågren
- Swedish Institute of Space Physics; Uppsala Sweden
| | - J. H. Waite
- Southwest Research Institute; San Antonio Texas USA
| | - M. K. Dougherty
- Space and Atmospheric Physics Group, Department of Physics; Imperial College London; London UK
| |
Collapse
|
25
|
Cui J, Galand M, Yelle RV, Vuitton V, Wahlund JE, Lavvas PP, Müller-Wodarg ICF, Cravens TE, Kasprzak WT, Waite JH. Diurnal variations of Titan's ionosphere. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009ja014228] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- J. Cui
- Space and Atmospheric Physics Group, Department of Physics; Imperial College; London UK
| | - M. Galand
- Space and Atmospheric Physics Group, Department of Physics; Imperial College; London UK
| | - R. V. Yelle
- Lunar and Planetary Laboratory; University of Arizona; Tucson Arizona USA
| | - V. Vuitton
- Laboratoire de Planétologie de Grenoble; Université Joseph Fourier/CNRS; Grenoble France
| | - J.-E. Wahlund
- Uppsala Division; Swedish Institute of Space Physics; Uppsala Sweden
| | - P. P. Lavvas
- Lunar and Planetary Laboratory; University of Arizona; Tucson Arizona USA
| | | | - T. E. Cravens
- Department of Physics and Astronomy; University of Kansas; Lawrence Kansas USA
| | - W. T. Kasprzak
- Solar System Exploration Division; NASA Goddard Space Flight Center; Greenbelt Maryland USA
| | - J. H. Waite
- Space Science and Engineering Division; Southwest Research Institute; San Antonio Texas USA
| |
Collapse
|
26
|
Affiliation(s)
| | - J. H. Waite
- Southwest Research Institute; San Antonio Texas USA
| | - T. E. Cravens
- Department of Physics and Astronomy; University of Kansas; Lawrence Kansas USA
| | - S. W. Bougher
- Department of Atmospheric, Oceanic and Space Sciences; University of Michigan; Ann Arbor Michigan USA
| | - I. P. Robertson
- Department of Physics and Astronomy; University of Kansas; Lawrence Kansas USA
| | - J. M. Bell
- Southwest Research Institute; San Antonio Texas USA
| |
Collapse
|
27
|
|
28
|
Abstract
The byssus of marine mussels has attracted attention as a paradigm of strong and versatile underwater adhesion. As the first of the 3,4-dihydroxyphenylalanine (Dopa)-containing byssal precursors to be purified, Mytilus edulis foot protein-1 (mefp-1) has been much investigated with respect to its molecular structure, physical properties, and adsorption to surfaces. Although mefp-1 undoubtedly contributes to the durability of byssus, it is not directly involved in adhesion. Rather, it provides a robust coating that is 4-5 times stiffer and harder than the byssal collagens that it covers. Protective coatings for compliant tissues and materials are highly appealing to technology, notwithstanding the conventional wisdom that coating extensibility can be increased only at the expense of hardness and stiffness. The byssal cuticle is the only known coating in which high compliance and hardness co-exist without mutual detriment; thus, the role of mefp-1 in accommodating both parameters deserves further study.
Collapse
Affiliation(s)
- N Holten-Andersen
- University of California at Santa Barbara, Santa Barbara, CA 93106, USA
| | | |
Collapse
|
29
|
Branduardi-Raymont G, Elsner RF, Galand M, Grodent D, Cravens TE, Ford P, Gladstone GR, Waite JH. Spectral morphology of the X-ray emission from Jupiter's aurorae. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007ja012600] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - R. F. Elsner
- NASA Marshall Space Flight Center; NSSTC/XD12, Space Science Branch; Huntsville Alabama USA
| | - M. Galand
- Imperial College London, Space and Atmospheric Physics Group; Blackett Laboratory; London UK
| | - D. Grodent
- Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique; Université de Liège; Liège Belgium
| | - T. E. Cravens
- Department of Physics and Astronomy; University of Kansas; Lawrence Kansas USA
| | - P. Ford
- Massachusetts Institute of Technology; Kavli Institute for Astrophysics and Space Research; Cambridge Massachusetts USA
| | | | - J. H. Waite
- Southwest Research Institute; San Antonio Texas USA
| |
Collapse
|
30
|
De La Haye V, Waite JH, Johnson RE, Yelle RV, Cravens TE, Luhmann JG, Kasprzak WT, Gell DA, Magee B, Leblanc F, Michael M, Jurac S, Robertson IP. Cassini Ion and Neutral Mass Spectrometer data in Titan's upper atmosphere and exosphere: Observation of a suprathermal corona. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006ja012222] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - J. H. Waite
- Southwest Research Institute; San Antonio Texas USA
| | - R. E. Johnson
- Astronomy Department; University of Virginia; Charlottesville Virginia USA
| | - R. V. Yelle
- Lunar and Planetary Laboratory; University of Arizona; Tucson Arizona USA
| | - T. E. Cravens
- Department of Physics and Astronomy; University of Kansas; Lawrence Kansas USA
| | - J. G. Luhmann
- Space Sciences Laboratory; University of California; Berkeley California USA
| | - W. T. Kasprzak
- NASA Goddard Space Flight Center; Greenbelt Maryland USA
| | - D. A. Gell
- Southwest Research Institute; San Antonio Texas USA
| | - B. Magee
- Southwest Research Institute; San Antonio Texas USA
| | - F. Leblanc
- Service d'Aéronomie du CNRS/IPSL; Paris France
| | - M. Michael
- Civil Engineering; Indian Institute of Technology; Kanpur India
| | - S. Jurac
- Center for Space Research; Massachusetts Institute of Technology; Cambridge Massachusetts USA
| | - I. P. Robertson
- Department of Physics and Astronomy; University of Kansas; Lawrence Kansas USA
| |
Collapse
|
31
|
Abstract
Titan's lower atmosphere has long been known to harbor organic aerosols (tholins) presumed to have been formed from simple molecules, such as methane and nitrogen (CH4 and N2). Up to now, it has been assumed that tholins were formed at altitudes of several hundred kilometers by processes as yet unobserved. Using measurements from a combination of mass/charge and energy/charge spectrometers on the Cassini spacecraft, we have obtained evidence for tholin formation at high altitudes (approximately 1000 kilometers) in Titan's atmosphere. The observed chemical mix strongly implies a series of chemical reactions and physical processes that lead from simple molecules (CH4 and N2) to larger, more complex molecules (80 to 350 daltons) to negatively charged massive molecules (approximately 8000 daltons), which we identify as tholins. That the process involves massive negatively charged molecules and aerosols is completely unexpected.
Collapse
Affiliation(s)
- J H Waite
- Space Science and Engineering Division, Southwest Research Institute (SWRI), 6220 Culebra Road, San Antonio, TX 78238, USA.
| | | | | | | | | | | | | |
Collapse
|
32
|
|
33
|
Moses DN, Mattoni MA, Slack NL, Waite JH, Zok FW. Role of melanin in mechanical properties of Glycera jaws. Acta Biomater 2006; 2:521-30. [PMID: 16831576 DOI: 10.1016/j.actbio.2006.05.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Revised: 04/03/2006] [Accepted: 05/04/2006] [Indexed: 10/24/2022]
Abstract
The remarkable mechanical prowess of the jaws of the bloodworm Glycera dibranchiata appears to be a consequence of a robust cross-linked network of organic molecules, notably melanin and proteins, as well as small amounts of unmineralized Cu and a Cu-based mineral. The present study focuses on the role of melanin. Mechanical properties of untreated jaws and the constituent melanin are probed through nanoindentation, both in air and underwater. Complementary information is obtained from density and porosity measurements and attempts at Cu removal from the jaws using EDTA, an effective metal chelator in most biological systems. In near-tip regions of the jaws, mechanical properties attain the highest values and diminish only slightly when wet (by 15-25%), in contrast to the behavior of other organic biomaterials. The melanin constituent contributes significantly to the mechanical integrity of the jaw; its hardness and elastic modulus are about half those of untreated jaws. Although melanin may be the dominant shape-determining component of the structure, it remains to be shown whether jaw assembly is mediated by protein deposition on a melanin scaffold or, conversely, by melanin deposition on a protein scaffold. The inability of EDTA to chelate Cu from the jaws and the relatively high density of the jaws and the melanin support the notion of a highly cross-linked molecular structure. Finally, based on the metric H(3)/E(2) (H being hardness and E the Young's modulus), the results suggest that the abrasion resistance of the jaws is superior to all engineering polymers and competitive with the hardest metallic alloys.
Collapse
Affiliation(s)
- D N Moses
- Materials Department, University of California, Santa Barbara, 93106-5050, USA
| | | | | | | | | |
Collapse
|
34
|
Cravens TE, Clark J, Bhardwaj A, Elsner R, Waite JH, Maurellis AN, Gladstone GR, Branduardi-Raymont G. X-ray emission from the outer planets: Albedo for scattering and fluorescence of solar X rays. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005ja011413] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
35
|
Waite JH, Cravens TE, Ip WH, Kasprzak WT, Luhmann JG, McNutt RL, Niemann HB, Yelle RV, Mueller-Wodarg I, Ledvina SA, Scherer S. Oxygen Ions Observed Near Saturn's A Ring. Science 2005; 307:1260-2. [PMID: 15731442 DOI: 10.1126/science.1105734] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Ions were detected in the vicinity of Saturn's A ring by the Ion and Neutral Mass Spectrometer (INMS) instrument onboard the Cassini Orbiter during the spacecraft's passage over the rings. The INMS saw signatures of molecular and atomic oxygen ions and of protons, thus demonstrating the existence of an ionosphere associated with the A ring. A likely explanation for these ions is photoionization by solar ultraviolet radiation of neutral O2 molecules associated with a tenuous ring atmosphere. INMS neutral measurements made during the ring encounter are dominated by a background signal.
Collapse
Affiliation(s)
- J H Waite
- Department of Atmospheric, Oceanic, and Space Physics, University of Michigan, Ann Arbor, MI 48109, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Majeed T, Waite JH, Bougher SW, Gladstone GR. Processes of equatorial thermal structure at Jupiter: An analysis of the Galileo temperature profile with a three-dimensional model. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004je002351] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
37
|
|
38
|
Clarke JT, Ajello J, Ballester G, Ben Jaffel L, Connerney J, Gérard JC, Gladstone GR, Grodent D, Pryor W, Trauger J, Waite JH. Ultraviolet emissions from the magnetic footprints of Io, Ganymede and Europa on Jupiter. Nature 2002; 415:997-1000. [PMID: 11875560 DOI: 10.1038/415997a] [Citation(s) in RCA: 177] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Io leaves a magnetic footprint on Jupiter's upper atmosphere that appears as a spot of ultraviolet emission that remains fixed underneath Io as Jupiter rotates. The specific physical mechanisms responsible for generating those emissions are not well understood, but in general the spot seems to arise because of an electromagnetic interaction between Jupiter's magnetic field and the plasma surrounding Io, driving currents of around 1 million amperes down through Jupiter's ionosphere. The other galilean satellites may also leave footprints, and the presence or absence of such footprints should illuminate the underlying physical mechanism by revealing the strengths of the currents linking the satellites to Jupiter. Here we report persistent, faint, far-ultraviolet emission from the jovian footprints of Ganymede and Europa. We also show that Io's magnetic footprint extends well beyond the immediate vicinity of Io's flux-tube interaction with Jupiter, and much farther than predicted theoretically; the emission persists for several hours downstream. We infer from these data that Ganymede and Europa have persistent interactions with Jupiter's magnetic field despite their thin atmospheres.
Collapse
Affiliation(s)
- J T Clarke
- Boston University, 725 Commonwealth Avenue, Boston, Massachusetts 02215, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Gladstone GR, Waite JH, Grodent D, Lewis WS, Crary FJ, Elsner RF, Weisskopf MC, Majeed T, Jahn JM, Bhardwaj A, Clarke JT, Young DT, Dougherty MK, Espinosa SA, Cravens TE. A pulsating auroral X-ray hot spot on Jupiter. Nature 2002; 415:1000-3. [PMID: 11875561 DOI: 10.1038/4151000a] [Citation(s) in RCA: 158] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Jupiter's X-ray aurora has been thought to be excited by energetic sulphur and oxygen ions precipitating from the inner magnetosphere into the planet's polar regions. Here we report high-spatial-resolution observations that demonstrate that most of Jupiter's northern auroral X-rays come from a 'hot spot' located significantly poleward of the latitudes connected to the inner magnetosphere. The hot spot seems to be fixed in magnetic latitude and longitude and occurs in a region where anomalous infrared and ultraviolet emissions have also been observed. We infer from the data that the particles that excite the aurora originate in the outer magnetosphere. The hot spot X-rays pulsate with an approximately 45-min period, a period similar to that reported for high-latitude radio and energetic electron bursts observed by near-Jupiter spacecraft. These results invalidate the idea that jovian auroral X-ray emissions are mainly excited by steady precipitation of energetic heavy ions from the inner magnetosphere. Instead, the X-rays seem to result from currently unexplained processes in the outer magnetosphere that produce highly localized and highly variable emissions over an extremely wide range of wavelengths.
Collapse
Affiliation(s)
- G R Gladstone
- Southwest Research Institute, San Antonio, Texas 78228, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Mauk BH, Clarke JT, Grodent D, Waite JH, Paranicas CP, Williams DJ. Transient aurora on Jupiter from injections of magnetospheric electrons. Nature 2002; 415:1003-5. [PMID: 11875562 DOI: 10.1038/4151003a] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Energetic electrons and ions that are trapped in Earth's magnetosphere can suddenly be accelerated towards the planet. Some dynamic features of Earth's aurora (the northern and southern lights) are created by the fraction of these injected particles that travels along magnetic field lines and hits the upper atmosphere. Jupiter's aurora appears similar to Earth's in some respects; both appear as large ovals circling the poles and both show transient events. But the magnetospheres of Jupiter and Earth are so different---particularly in the way they are powered---that it is not known whether the magnetospheric drivers of Earth's aurora also cause them on Jupiter. Here we show a direct relationship between Earth-like injections of electrons in Jupiter's magnetosphere and a transient auroral feature in Jupiter's polar region. This relationship is remarkably similar to what happens at Earth, and therefore suggests that despite the large differences between planetary magnetospheres, some processes that generate aurorae are the same throughout the Solar System.
Collapse
Affiliation(s)
- B H Mauk
- The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, USA.
| | | | | | | | | | | |
Collapse
|
41
|
Abstract
Byssal threads provide marine mussels with the tenacity to remain sessile in habitats of high flow. Under uniaxial tension, byssal threads are typical of other biological and synthetic fibers in exhibiting an initial linear region followed by yield. They differ, however, in their capacity to recover or "self-heal" following yield. We have examined the effect of urea, dithiothreitol (DTT), and metal-chelating agents such as ethylenediamine tetraacetic acid (EDTA) in perturbing the modulus, yield point, and energy dissipated in distal byssal threads stretched cyclically in seawater to a strain of 0.7. Threads stretched in the presence of 8 M urea or DTT show a complete abolition of yield point, while those washed clean of urea and DTT prior to stretching approach native controls. Threads stretched in the presence of EDTA show no effect; however, preincubation of distal threads in EDTA for 24 h results in a loss of yield point if stretched in metal-deficient seawater and normal behavior in natural seawater. The results indicate that while protein unfolding and disruption of disulfide linkages or chelate complexes compromises the yield strength of distal byssal fibers, there is typically a rapid recovery in natural sea water.
Collapse
Affiliation(s)
- E Vaccaro
- Marine Science Institute and Molecular, Cellular and Developmental Biology Department, University of California at Santa Barbara, Santa Barbara, California 93106, USA
| | | |
Collapse
|
42
|
Abstract
The byssal threads of marine mussels are a fiber-reinforced composite material. Fibers are continuous, separated by matrix, and consist of chimeric collagens that encompass within the same primary protein structure domains corresponding to collagen, polyhistidine, and either elastin or dragline spider silk. The elastic modulus (stiffness) of the proximal portion of byssal threads was measured by cyclic stress-strain analysis at 50% extension. Before measurement, the threads were conditioned by various treatments, particularly agitation in aerated or nitrogen-sparged seawater. Stiffness can be permanently increased by more than two times, e.g., from 25 MPa to a maximum of 65 MPa, by simple agitation in aerated seawater. Much but not all of this stiffening can be prevented by agitation under nitrogen. Reversible strain stiffening would seem to be a useful adaptation to lower residual stresses arising from the deformation of two joined materials, i.e., distal and proximal portions with rather different elastic moduli. The permanent strain stiffening that characterizes proximal byssal threads subjected to oxidative stress is probably due to protein cross-linking. In the short term, this results in a stronger thread but at the expense of dynamic interactions between the molecules in the structure.
Collapse
Affiliation(s)
- C Sun
- Marine Science Institute and MCDB Department, University of California at Santa Barbara, Santa Barbara, California 93106, USA
| | | | | |
Collapse
|
43
|
Abstract
The development of the vitellaria of Fasciola hepatica within the liver of its rat host was studied by means of whole-mount stained preparations and transmission electron microscopy, together with light and electron immunocytochemistry using an antibody to vitelline protein B, an eggshell precursor protein synthesized by F. hepatica. No vitelline cells could be identified in flukes recovered from the liver parenchyma, by any of the methods used. In contrast, follicles were present in flukes at the earliest time of recovery from the bile duct, namely, 5 weeks 3 days post-infection. The vitellaria in these flukes formed a row of small follicles on either side of the body. Development of the follicles was rapid: by 6 weeks 3 days, the vitellaria resembled those in the adult fluke and eggs were present in the uterus. Immunolabelling was confined to the shell protein globules in the vitelline cells, confirming the packaging of the eggshell protein within the shell globule clusters.
Collapse
Affiliation(s)
- M W Robinson
- Fascioliasis Research Group, The School of Biology and Biochemistry, The Queen's University of Belfast, Northern Ireland
| | | | | | | | | |
Collapse
|
44
|
Waite JH, Gladstone GR, Lewis WS, Goldstein R, McComas DJ, Riley P, Walker RJ, Robertson P, Desai S, Clarke JT, Young DT. An auroral flare at Jupiter. Nature 2001; 410:787-9. [PMID: 11298440 DOI: 10.1038/35071018] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Jupiter's aurora is the most powerful in the Solar System. It is powered largely by energy extracted from planetary rotation, although there seems also to be a contribution from the solar wind. This contrasts with Earth's aurora, which is generated through the interaction of the solar wind with the magnetosphere. The major features of Jupiter's aurora (based on far-ultraviolet, near-infrared and visible-wavelength observations) include a main oval that generally corotates with the planet and a region of patchy, diffuse emission inside the oval on Jupiter's dusk side. Here we report the discovery of a rapidly evolving, very bright and localized emission poleward of the northern main oval, in a region connected magnetically to Jupiter's outer magnetosphere. The intensity of the emission increased by a factor of 30 within 70 s, and then decreased on a similar timescale, all captured during a single four-minute exposure. This type of flaring emission has not previously been reported for Jupiter (similar, but smaller, transient events have been observed at Earth), and it may be related directly to changes in the solar wind.
Collapse
Affiliation(s)
- J H Waite
- Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Abstract
Tyrosine residues of neuroendocrine peptides are frequently the targets of oxidation reactions, one of which involves hydroxylation to peptidyl-3, 4-dihydroxy-phenyl-L-alanine (DOPA). The reactivity in vitro of peptidyl-DOPA in two neuroendocrine peptides, a neurotensin fragment (pELYENK) and proctolin (RYLPT), was investigated using ultraviolet-visible scanning spectrophotometry and matrix-assisted laser desorption ionization mass spectrometry following oxidation by tyrosinase and periodate. The peptides form covalently coupled dimers and trimers, and their masses are consistent with the presence of diDOPA cross-links. Lysine does not appear to participate in multimer formation because it is efficiently recovered in fragmentation ladders using subtilisin. While multimer formation in the neurotensin-derived peptide can be blocked effectively by adding N-acetyl-DOPA-ethylester to the reaction medium, the DOPA ethylester couples itself four to five times to each peptide.
Collapse
Affiliation(s)
- L A Burzio
- Surgical Sealants, Inc., Woburn, Massachusetts 01801, USA.
| | | |
Collapse
|
46
|
Abstract
Achieving a satisfactory biochemical explanation for the opportunistic underwater adhesion of marine invertebrates such as mussels and barnacles requires a detailed characterization of proteins extracted from holdfast structures produced by these organisms. Mefp-5 is an adhesive protein derived from the foot of the common mussel, Mytilus edulis, and deposited into the byssal attachment pads. Purification and primary structure of mefp-5 was determined by peptide mapping and cDNA sequencing. The protein is 74 residues long and has a mass of about 9500 Da. Mefp-5 composition shows a strong amino acid bias: aromatic amino acids, lysine, and glycine represent 65 mol % of the composition. More than a third of all the residues in the protein are posttranslationally modified by hydroxylation or phosphorylation. The conversion of tyrosine to 3, 4-dihydroxyphenyl-L-alanine (DOPA) and serine to O-phosphoserine accounts for the hydroxylation and phosphorylation, respectively. Neither modification is complete since variations in the extent of phosphorylation and hydroxylation can be detected by mass spectrometry. More than 75% of the DOPA is adjacent to basic residues, e.g., Lys-DOPA and DOPA-Lys. Phosphoserine occurs in sequences strikingly reminiscent of acidic mineral-binding motifs that appear in statherin, osteopontin, and others. This may be an adaptation for adhesion to the most common substrata for mussels, i.e., calcareous materials.
Collapse
Affiliation(s)
- J H Waite
- Department of Cell Biology, Duke University, Durham, North Carolina 27706, USA.
| | | |
Collapse
|
47
|
Abstract
The zebra mussel is one of only a few freshwater bivalves known to produce a byssus. This fibrous, proteinaceous and highly cross-linked structure allows the mussel to attach to a variety of substrata and contributes to its notoriety as a major freshwater biofouling species. We have successfully expressed a full-length version of Dreissena polymorpha foot protein 1 (Dpfp1), a putative byssal thread precursor, and have used the recombinant protein as an antigen for polyclonal antibody production. Antisera obtained from rabbits immunized with recombinant Dpfp1 recognize the protein in western blots of extracts from foot tissue and byssal threads. On the basis of this evidence, we conclude that Dpfp1 is a byssal precursor protein manufactured and stored in the foot of the mussel. Immunohistochemical localization of Dpfp1 suggests that the protein is localized in secretory granules in a large gland surrounding the ventral groove of the foot. Only a subset of these glandular cells stockpiles the protein, implying that the zebra mussel foot is a complex organ capable of several distinct secretory activities involved in byssal thread formation. The uniform distribution of Dpfp1-containing cells suggests that the protein is a significant load-bearing component of zebra mussel byssal threads, although a more rigorous test of this hypothesis awaits ultrastructural localization of the protein in mature byssal threads.
Collapse
Affiliation(s)
- K E Anderson
- Department of Bioengineering, Box 357962, University of Washington, Seattle, WA 98195, USA.
| | | |
Collapse
|
48
|
Abstract
Mytilus edulis foot protein-1 (mefp1) is a major component of the byssus, an adhesive holdfast in mussels. The recent report of 5, 5'-di(dihydroxyphenyl-L-alanine) (diDOPA) cross-links in byssus [McDowell et al. (1999) J. Biol. Chem. 274, 20293] has raised questions about the relationship of these to mefp1. About 80% of the primary structure of mefp1 consists of a tandemly repeated consensus sequence Ala(1)-Lys(2)-Pro(3)-Ser(4)-Tyr(5)-Pro(6)-Pro(7)-Thr(8)-Tyr(9)-Lys(10 ) with varying degrees of posttranslational hydroxylation to hydroxyprolines in positions 3, 6, and 7 and to DOPA in positions 5 and 9. Six natural or synthetic variants of this decapeptide were subjected to oxidation by tyrosinase or periodate. DOPA is the only residue to suffer losses in all oxidized peptides. Moreover, using MALDI TOF mass spectrometry, oxidized decapeptides all showed evidence of multimer formation and a mass loss of 6 Da per coupled pair of peptides. Multimer formation was inhibited by addition of DOPA-like o-diphenols, but addition of simple amines such as free Lys had no effect. The results are consistent with aryloxy coupling to diDOPA followed by reoxidation to diDOPA quinone. There are subtle but noteworthy variations, however, in multimer formation among the peptide congeners. Decapeptides with Pro(3) modified to trans-4-hydroxyproline do not form multimers beyond dimers; they also exhibit significant Lys losses following oxidation of DOPA. Moreover, in Ala-Lys-Hyp-Ser-Tyr-DiHyp-Hyp-Thr-DOPA-Lys, Tyr appears to be protected from oxidation by tyrosinase.
Collapse
Affiliation(s)
- L A Burzio
- Marine Science Institute/MCDB Department, University of California, Santa Barbara, California 93106, USA
| | | |
Collapse
|
49
|
Floriolli RY, Waite JH. Marine Surfaces and the Expression of Specific Byssal Adhesive Protein Variants in Mytilus. Mar Biotechnol (NY) 2000; 2:352-363. [PMID: 10960125 DOI: 10.1007/s101269900032] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Mytilus foot protein-3 (Mfp-3) is a highly polymorphic protein family located in the byssal adhesive plaques of blue mussels. Previous evidence suggested that the deposition of selected Mfp-3 variants might be influenced by the type of surface to which the mussel attaches; therefore, we undertook to rigorously investigate whether a correlation exists between surface type and Mfp-3 variants. Two hypotheses were tested in M. galloprovincialis and M. edulis. One hypothesis was that individual mussels deposit specific Mfp-3 variants on different surfaces. Laser desorption-ionization mass spectrometry was used to detect Mfp-3 variants on the underside of byssal adhesive plaques. The other hypothesis was that the transcription of specific Mfp-3s is induced by different surfaces. This was measured by using denaturing gradient gel electrophoresis to separate closely related amplified complementary DNAs among individual mussels attached to stainless steel, glass, or polyethylene surfaces. Band stabs of several Mfp-3 cDNAs were sequenced. The results clearly showed that individual mussels secreted a similar suite of Mfp-3 variants onto glass, plastic, and steel. Likewise, the expression of Mfp-3 cDNA transcripts in individual mussels revealed no clear correlation between messenger RNA expression and the type of surface. Thus, the expression and secretion of specific Mfp-3 variants do not appear to be surface-induced. These results underscore the importance of following individual mussels rather than populations in surface studies.
Collapse
Affiliation(s)
- RY Floriolli
- College of Marine Studies, University of Delaware, Lewes, DE 19958, U.S.A
| | | |
Collapse
|
50
|
Burzio LA, Saéz C, Pardo J, Waite JH, Burzio LO. The adhesive protein of Choromytilus chorus (Molina, 1782) and Aulacomya ater (Molina, 1782): a proline-rich and a glycine-rich polyphenolic protein. Biochim Biophys Acta 2000; 1479:315-20. [PMID: 11004549 DOI: 10.1016/s0167-4838(00)00010-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The adhesive polyphenolic proteins from Aulacomya ater and Choromytilus chorus with apparent molecular masses of 135000 and 105000, respectively, were digested with trypsin and the peptides produced resolved by reversed phase liquid chromatography. About 5 and 12 major peptides were obtained from the protein of A. ater and C. chorus, respectively. The major peptides were purified by reverse-phase chromatography and the amino acid sequence indicates that both polyphenolic proteins consisted of repeated sequence motifs in their primary structure. The major peptides of A. ater contain seven amino acids corresponding to the consensus sequence AGYGGXK, whereas the tyrosine was always found as 3, 4-dihydroxyphenylalanine (Dopa), the X residue in position 6 was either valine, leucine or isoleucine, and the carboxy terminal was either lysine or hydroxylysine. On the other hand, the major peptides of C. chorus ranged in size from 6 to 21 amino acids and the majority correspond to the consensus sequence AKPSKYPTGYKPPVK. Both proteins differ markedly in the sequence of their tryptic peptides, but they share the common characteristics of other adhesive proteins in having a tandem sequence repeat in their primary structure.
Collapse
Affiliation(s)
- L A Burzio
- BiosChile Ingenieria Genética S.A., Santiago, Chile
| | | | | | | | | |
Collapse
|