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Wong MH, Rowe-Gurney N, Markham S, Sayanagi KM. Multiple Probe Measurements at Uranus Motivated by Spatial Variability. SPACE SCIENCE REVIEWS 2024; 220:15. [PMID: 38343766 PMCID: PMC10858001 DOI: 10.1007/s11214-024-01050-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 01/18/2024] [Indexed: 02/22/2024]
Abstract
A major motivation for multiple atmospheric probe measurements at Uranus is the understanding of dynamic processes that create and maintain spatial variation in thermal structure, composition, and horizontal winds. But origin questions-regarding the planet's formation and evolution, and conditions in the protoplanetary disk-are also major science drivers for multiprobe exploration. Spatial variation in thermal structure reveals how the atmosphere transports heat from the interior, and measuring compositional variability in the atmosphere is key to ultimately gaining an understanding of the bulk abundances of several heavy elements. We review the current knowledge of spatial variability in Uranus' atmosphere, and we outline how multiple probe exploration would advance our understanding of this variability. The other giant planets are discussed, both to connect multiprobe exploration of those atmospheres to open questions at Uranus, and to demonstrate how multiprobe exploration of Uranus itself is motivated by lessons learned about the spatial variation at Jupiter, Saturn, and Neptune. We outline the measurements of highest value from miniature secondary probes (which would complement more detailed investigation by a larger flagship probe), and present the path toward overcoming current challenges and uncertainties in areas including mission design, cost, trajectory, instrument maturity, power, and timeline.
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Affiliation(s)
- Michael H. Wong
- Center for Integrative Planetary Science, University of California, Berkeley, CA 94720-3411 USA
- Carl Sagan Center for Science, SETI Institute, Mountain View, CA 94043-5232 USA
| | - Naomi Rowe-Gurney
- NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA
- University of Maryland, College Park, MD 20742 USA
- The Center for Research and Exploration in Space Science & Technology (CRESST II), Greenbelt, MD 20771 USA
- The Royal Astronomical Society, Piccadilly, London, W1J 0BD UK
| | - Stephen Markham
- Observatoire de la Côte d’Azur, 06300 Nice, France
- Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 USA
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2
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Fletcher LN, Cavalié T, Grassi D, Hueso R, Lara LM, Kaspi Y, Galanti E, Greathouse TK, Molyneux PM, Galand M, Vallat C, Witasse O, Lorente R, Hartogh P, Poulet F, Langevin Y, Palumbo P, Gladstone GR, Retherford KD, Dougherty MK, Wahlund JE, Barabash S, Iess L, Bruzzone L, Hussmann H, Gurvits LI, Santolik O, Kolmasova I, Fischer G, Müller-Wodarg I, Piccioni G, Fouchet T, Gérard JC, Sánchez-Lavega A, Irwin PGJ, Grodent D, Altieri F, Mura A, Drossart P, Kammer J, Giles R, Cazaux S, Jones G, Smirnova M, Lellouch E, Medvedev AS, Moreno R, Rezac L, Coustenis A, Costa M. Jupiter Science Enabled by ESA's Jupiter Icy Moons Explorer. SPACE SCIENCE REVIEWS 2023; 219:53. [PMID: 37744214 PMCID: PMC10511624 DOI: 10.1007/s11214-023-00996-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 08/10/2023] [Indexed: 09/26/2023]
Abstract
ESA's Jupiter Icy Moons Explorer (JUICE) will provide a detailed investigation of the Jovian system in the 2030s, combining a suite of state-of-the-art instruments with an orbital tour tailored to maximise observing opportunities. We review the Jupiter science enabled by the JUICE mission, building on the legacy of discoveries from the Galileo, Cassini, and Juno missions, alongside ground- and space-based observatories. We focus on remote sensing of the climate, meteorology, and chemistry of the atmosphere and auroras from the cloud-forming weather layer, through the upper troposphere, into the stratosphere and ionosphere. The Jupiter orbital tour provides a wealth of opportunities for atmospheric and auroral science: global perspectives with its near-equatorial and inclined phases, sampling all phase angles from dayside to nightside, and investigating phenomena evolving on timescales from minutes to months. The remote sensing payload spans far-UV spectroscopy (50-210 nm), visible imaging (340-1080 nm), visible/near-infrared spectroscopy (0.49-5.56 μm), and sub-millimetre sounding (near 530-625 GHz and 1067-1275 GHz). This is coupled to radio, stellar, and solar occultation opportunities to explore the atmosphere at high vertical resolution; and radio and plasma wave measurements of electric discharges in the Jovian atmosphere and auroras. Cross-disciplinary scientific investigations enable JUICE to explore coupling processes in giant planet atmospheres, to show how the atmosphere is connected to (i) the deep circulation and composition of the hydrogen-dominated interior; and (ii) to the currents and charged particle environments of the external magnetosphere. JUICE will provide a comprehensive characterisation of the atmosphere and auroras of this archetypal giant planet.
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Affiliation(s)
- Leigh N. Fletcher
- School of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH UK
| | - Thibault Cavalié
- Laboratoire d’Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
- LESIA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CNRS, 5 place Jules Janssen, 92195 Meudon, France
| | - Davide Grassi
- Istituto di Astrofisica e Planetologia Spaziali - Istituto Nazionale di Astrofisica, Via del Fosso del Cavaliere, 100, I-00133 Roma, Italy
| | - Ricardo Hueso
- Física Aplicada, Escuela de Ingeniería de Bilbao Universidad del País Vasco UPV/EHU, Plaza Ingeniero Torres Quevedo, 1, 48013 Bilbao, Spain
| | - Luisa M. Lara
- Instituto de Astrofísica de Andalucía-CSIC, c/Glorieta de la Astronomía 3, 18008 Granada, Spain
| | - Yohai Kaspi
- Dept. of Earth and Planetray Science, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Eli Galanti
- Dept. of Earth and Planetray Science, Weizmann Institute of Science, Rehovot, Israel 76100
| | | | | | - Marina Galand
- Department of Physics, Imperial College London, Prince Consort Road, London, SW7 2AZ UK
| | - Claire Vallat
- European Space Agency (ESA), ESAC Camino Bajo del Castillo s/n Villafranca del Castillo, 28692 Villanueva de la Cañada (Madrid), Spain
| | - Olivier Witasse
- European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Noordwijk, Netherlands
| | - Rosario Lorente
- European Space Agency (ESA), ESAC Camino Bajo del Castillo s/n Villafranca del Castillo, 28692 Villanueva de la Cañada (Madrid), Spain
| | - Paul Hartogh
- Max-Planck-Institut für Sonnensystemforschung, 37077 Göttingen, Germany
| | - François Poulet
- Institut d’Astrophysique Spatiale, CNRS/Université Paris-Sud, 91405 Orsay Cedex, France
| | - Yves Langevin
- Institut d’Astrophysique Spatiale, CNRS/Université Paris-Sud, 91405 Orsay Cedex, France
| | - Pasquale Palumbo
- Istituto di Astrofisica e Planetologia Spaziali - Istituto Nazionale di Astrofisica, Via del Fosso del Cavaliere, 100, I-00133 Roma, Italy
| | - G. Randall Gladstone
- Southwest Research Institute, San Antonio, TX 78228 United States
- University of Texas at San Antonio, San Antonio, TX United States
| | - Kurt D. Retherford
- Southwest Research Institute, San Antonio, TX 78228 United States
- University of Texas at San Antonio, San Antonio, TX United States
| | | | | | - Stas Barabash
- Swedish Institute of Space Physics (IRF), Kiruna, Sweden
| | - Luciano Iess
- Dipartimento di ingegneria meccanica e aerospaziale, Universit á La Sapienza, Roma, Italy
| | - Lorenzo Bruzzone
- Department of Information Engineering and Computer Science, Remote Sensing Laboratory, University of Trento, Via Sommarive 14, Trento, I-38123 Italy
| | - Hauke Hussmann
- Deutsches Zentrum für Luft- und Raumfahrt (DLR), Berlin, Germany
| | - Leonid I. Gurvits
- Joint Institute for VLBI ERIC, Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, The Netherlands
- Aerospace Faculty, Delft University of Technology, Kluyverweg 1, 2629 HS Delft, The Netherlands
| | - Ondřej Santolik
- Department of Space Physics, Institute of Atmospheric Physics of the Czech Academy of Sciences, Prague, Czechia
- Faculty of Mathematics and Physics, Charles University, Prague, Czechia
| | - Ivana Kolmasova
- Department of Space Physics, Institute of Atmospheric Physics of the Czech Academy of Sciences, Prague, Czechia
- Faculty of Mathematics and Physics, Charles University, Prague, Czechia
| | - Georg Fischer
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | | | - Giuseppe Piccioni
- Istituto di Astrofisica e Planetologia Spaziali - Istituto Nazionale di Astrofisica, Via del Fosso del Cavaliere, 100, I-00133 Roma, Italy
| | - Thierry Fouchet
- LESIA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CNRS, 5 place Jules Janssen, 92195 Meudon, France
| | | | - Agustin Sánchez-Lavega
- Física Aplicada, Escuela de Ingeniería de Bilbao Universidad del País Vasco UPV/EHU, Plaza Ingeniero Torres Quevedo, 1, 48013 Bilbao, Spain
| | - Patrick G. J. Irwin
- Atmospheric, Oceanic and Planetary Physics, Department of Physics, University of Oxford, Parks Rd, Oxford, OX1 3PU UK
| | - Denis Grodent
- LPAP, STAR Institute, Université de Liège, Liège, Belgium
| | - Francesca Altieri
- Istituto di Astrofisica e Planetologia Spaziali - Istituto Nazionale di Astrofisica, Via del Fosso del Cavaliere, 100, I-00133 Roma, Italy
| | - Alessandro Mura
- Istituto di Astrofisica e Planetologia Spaziali - Istituto Nazionale di Astrofisica, Via del Fosso del Cavaliere, 100, I-00133 Roma, Italy
| | - Pierre Drossart
- LESIA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CNRS, 5 place Jules Janssen, 92195 Meudon, France
- Institut d’Astrophysique de Paris, CNRS, Sorbonne Université, 98bis Boulevard Arago, 75014 Paris, France
| | - Josh Kammer
- Southwest Research Institute, San Antonio, TX 78228 United States
| | - Rohini Giles
- Southwest Research Institute, San Antonio, TX 78228 United States
| | - Stéphanie Cazaux
- Faculty of Aerospace Engineering, Delft University of Technology, Delft, The Netherlands
| | - Geraint Jones
- UCL Mullard Space Science Laboratory, Hombury St. Mary, Dorking, RH5 6NT UK
- The Centre for Planetary Sciences at UCL/Birkbeck, London, WC1E 6BT UK
| | - Maria Smirnova
- Dept. of Earth and Planetray Science, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Emmanuel Lellouch
- LESIA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CNRS, 5 place Jules Janssen, 92195 Meudon, France
| | | | - Raphael Moreno
- LESIA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CNRS, 5 place Jules Janssen, 92195 Meudon, France
| | - Ladislav Rezac
- Max-Planck-Institut für Sonnensystemforschung, 37077 Göttingen, Germany
| | - Athena Coustenis
- LESIA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CNRS, 5 place Jules Janssen, 92195 Meudon, France
| | - Marc Costa
- Rhea Group, for European Space Agency, ESAC, Madrid, Spain
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3
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Li C, de Pater I, Moeckel C, Sault RJ, Butler B, deBoer D, Zhang Z. Long-lasting, deep effect of Saturn's giant storms. SCIENCE ADVANCES 2023; 9:eadg9419. [PMID: 37566653 PMCID: PMC10421028 DOI: 10.1126/sciadv.adg9419] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 07/12/2023] [Indexed: 08/13/2023]
Abstract
Planetary-scale giant storms erupt on Saturn quasiperiodically. There have been at least six recorded occurrences of past eruptions, and the most recent one was in 2010, with its whole life span captured by the Cassini mission. In 2015, we used the Very Large Array to probe the deep response of Saturn's troposphere to the giant storms. In addition to the remnant effect of the storm in 2010, we have found long-lasting signatures of all mid-latitude giant storms, a mixture of equatorial storms up to hundreds of years old, and potentially an unreported older storm at 70°N. We derive an ammonia anomaly map that shows an extended meridional migration of the storm's aftermath and vertical transport of ammonia vapor by storm dynamics. Intriguingly, the last storm in 2010 splits into two distinct components that propagate in opposite meridional directions, leaving a gap at 43°N planetographic latitude.
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Affiliation(s)
- Cheng Li
- Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Imke de Pater
- Department of Astronomy, University of California, Berkeley, Berkeley, CA, USA
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, USA
| | - Chris Moeckel
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, USA
| | - R. J. Sault
- School of Physics, University of Melbourne, Victoria 3010, Australia
| | - Bryan Butler
- National Radio Astronomy Observatory, Socorro, NM, USA
| | - David deBoer
- Department of Astronomy, University of California, Berkeley, Berkeley, CA, USA
| | - Zhimeng Zhang
- Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
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4
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Ingersoll AP, Atreya S, Bolton SJ, Brueshaber S, Fletcher LN, Levin SM, Li C, Li L, Lunine JI, Orton GS, Waite H. Jupiter's Overturning Circulation: Breaking Waves Take the Place of Solid Boundaries. GEOPHYSICAL RESEARCH LETTERS 2021; 48:e2021GL095756. [PMID: 35027778 PMCID: PMC8753638 DOI: 10.1029/2021gl095756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 10/06/2021] [Accepted: 10/12/2021] [Indexed: 06/14/2023]
Abstract
Cloud-tracked wind observations document the role of eddies in putting momentum into the zonal jets. Chemical tracers, lightning, clouds, and temperature anomalies document the rising and sinking in the belts and zones, but questions remain about what drives the flow between the belts and zones. We suggest an additional role for the eddies, which is to generate waves that propagate both up and down from the cloud layer. When the waves break they deposit momentum and thereby replace the friction forces at solid boundaries that enable overturning circulations on terrestrial planets. By depositing momentum of one sign within the cloud layer and momentum of the opposite sign above and below the clouds, the eddies maintain all components of the circulation, including the stacked, oppositely rotating cells between each belt-zone pair, and the zonal jets themselves.
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Affiliation(s)
- Andrew P. Ingersoll
- Division of Geological and Planetary SciencesCalifornia Institute of TechnologyPasadenaCAUSA
| | - Sushil Atreya
- Climate and Space SciencesUniversity of MichiganAnn ArborMIUSA
| | | | - Shawn Brueshaber
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | | | - Steven M. Levin
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Cheng Li
- Climate and Space SciencesUniversity of MichiganAnn ArborMIUSA
| | - Liming Li
- Department of PhysicsUniversity of HoustonHoustonTXUSA
| | | | - Glenn S. Orton
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Hunter Waite
- Space ScienceSouthwest Research InstituteSan AntonioTXUSA
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5
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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: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
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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
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Hueso R, Guillot T, Sánchez-Lavega A. Convective storms and atmospheric vertical structure in Uranus and Neptune. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190476. [PMID: 33161859 PMCID: PMC7658788 DOI: 10.1098/rsta.2019.0476] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/27/2020] [Indexed: 05/20/2023]
Abstract
The ice giants Uranus and Neptune have hydrogen-based atmospheres with several constituents that condense in their cold upper atmospheres. A small number of bright cloud systems observed in both planets are good candidates for moist convective storms, but their observed properties (size, temporal scales and cycles of activity) differ from moist convective storms in the gas giants. These clouds and storms are possibly due to methane condensation and observations also suggest deeper clouds of hydrogen sulfide (H2S) at depths of a few bars. Even deeper, thermochemical models predict clouds of ammonia hydrosulfide (NH4SH) and water at pressures of tens to hundreds of bars, forming extended deep weather layers. Because of hydrogen's low molecular weight and the high abundance of volatiles, their condensation imposes a strongly stabilizing vertical gradient of molecular weight larger than the equivalent one in Jupiter and Saturn. The resulting inhibition of vertical motions should lead to a moist convective regime that differs significantly from the one occurring on nitrogen-based atmospheres like those of Earth or Titan. As a consequence, the thermal structure of the deep atmospheres of Uranus and Neptune is not well understood. Similar processes might occur at the deep water cloud of Jupiter in Saturn, but the ice giants offer the possibility to study these physical aspects in the upper methane cloud layer. A combination of orbital and in situ data will be required to understand convection and its role in atmospheric dynamics in the ice giants, and by extension, in hydrogen atmospheres including Jupiter, Saturn and giant exoplanets. This article is part of a discussion meeting issue 'Future exploration of ice giant systems'.
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Affiliation(s)
- R. Hueso
- Física Aplicada I, Escuela de Ingeniería de Bilbao, UPV/EHU, 48013 Bilbao, Spain
| | - T. Guillot
- Université Côte d’Azur, Laboratoire Lagrange, OCA, CNRS UMR 7293, Nice, France
| | - A. Sánchez-Lavega
- Física Aplicada I, Escuela de Ingeniería de Bilbao, UPV/EHU, 48013 Bilbao, Spain
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7
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Teanby NA, Irwin PGJ, Moses JI, Helled R. Neptune and Uranus: ice or rock giants? PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190489. [PMID: 33161863 PMCID: PMC7658781 DOI: 10.1098/rsta.2019.0489] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/04/2020] [Indexed: 05/20/2023]
Abstract
Existing observations of Uranus and Neptune's fundamental physical properties can be fitted with a wide range of interior models. A key parameter in these models is the bulk rock:ice ratio and models broadly fall into ice-dominated (ice giant) and rock-dominated (rock giant) categories. Here we consider how observations of Neptune's atmospheric temperature and composition (H2, He, D/H, CO, CH4, H2O and CS) can provide further constraints. The tropospheric CO profile in particular is highly diagnostic of interior ice content, but is also controversial, with deep values ranging from zero to 0.5 parts per million. Most existing CO profiles imply extreme O/H enrichments of >250 times solar composition, thus favouring an ice giant. However, such high O/H enrichment is not consistent with D/H observations for a fully mixed and equilibrated Neptune. CO and D/H measurements can be reconciled if there is incomplete interior mixing (ice giant) or if tropospheric CO has a solely external source and only exists in the upper troposphere (rock giant). An interior with more rock than ice is also more compatible with likely outer solar system ice sources. We primarily consider Neptune, but similar arguments apply to Uranus, which has comparable C/H and D/H enrichment, but no observed tropospheric CO. While both ice- and rock-dominated models are viable, we suggest a rock giant provides a more consistent match to available atmospheric observations. This article is part of a discussion meeting issue 'Future exploration of ice giant systems'.
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Affiliation(s)
- N. A. Teanby
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK
| | - P. G. J. Irwin
- Atmospheric, Oceanic and Planetary Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK
| | - J. I. Moses
- Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA
| | - R. Helled
- Institute for Computational Science, Center for Theoretical Astrophysics and Cosmology, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
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8
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Wakeford HR, Dalba PA. The exoplanet perspective on future ice giant exploration. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20200054. [PMID: 33161853 DOI: 10.1098/rsta.2020.0054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/06/2020] [Indexed: 05/20/2023]
Abstract
Exoplanets number in their thousands, and the number is ever increasing with the advent of new surveys and improved instrumentation. One of the most surprising things we have learnt from these discoveries is not that small-rocky planets in their stars habitable zones are likely to be common, but that the most typical size of exoplanets is that not seen in our solar system-radii between that of Neptune and the Earth dubbed mini-Neptunes and super-Earths. In fact, a transiting exoplanet is four times as likely to be in this size regime than that of any giant planet in our solar system. Investigations into the atmospheres of giant hydrogen/helium dominated exoplanets has pushed down to Neptune and mini-Neptune-sized worlds revealing molecular absorption from water, scattering and opacity from clouds, and measurements of atmospheric abundances. However, unlike measurements of Jupiter, or even Saturn sized worlds, the smaller giants lack a ground truth on what to expect or interpret from their measurements. How did these sized worlds form and evolve and was it different from their larger counterparts? What is their internal composition and how does that impact their atmosphere? What informs the energy budget of these distant worlds? In this we discuss what characteristics we can measure for exoplanets, and why a mission to the ice giants in our solar system is the logical next step for understanding exoplanets. This article is part of a discussion meeting issue 'Future exploration of ice giant systems'.
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Affiliation(s)
- H R Wakeford
- School of Physics, University of Bristol, HH Wills Laboratory, Tyndall Avenue, Bristol BS8 1TL, UK
| | - P A Dalba
- Department of Earth and Planetary Sciences, University of California Riverside, 900 University Avenue, Riverside CA 92521, USA
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9
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Moses JI, Cavalié T, Fletcher LN, Roman MT. Atmospheric chemistry on Uranus and Neptune. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190477. [PMID: 33161866 PMCID: PMC7658780 DOI: 10.1098/rsta.2019.0477] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/16/2020] [Indexed: 05/04/2023]
Abstract
Comparatively little is known about atmospheric chemistry on Uranus and Neptune, because remote spectral observations of these cold, distant 'Ice Giants' are challenging, and each planet has only been visited by a single spacecraft during brief flybys in the 1980s. Thermochemical equilibrium is expected to control the composition in the deeper, hotter regions of the atmosphere on both planets, but disequilibrium chemical processes such as transport-induced quenching and photochemistry alter the composition in the upper atmospheric regions that can be probed remotely. Surprising disparities in the abundance of disequilibrium chemical products between the two planets point to significant differences in atmospheric transport. The atmospheric composition of Uranus and Neptune can provide critical clues for unravelling details of planet formation and evolution, but only if it is fully understood how and why atmospheric constituents vary in a three-dimensional sense and how material coming in from outside the planet affects observed abundances. Future mission planning should take into account the key outstanding questions that remain unanswered about atmospheric chemistry on Uranus and Neptune, particularly those questions that pertain to planet formation and evolution, and those that address the complex, coupled atmospheric processes that operate on Ice Giants within our solar system and beyond. This article is part of a discussion meeting issue 'Future exploration of ice giant systems'.
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Affiliation(s)
- J. I. Moses
- Space Science Institute, 4765 Walnut Street, Suite B, Boulder, CO 80301, USA
| | - T. Cavalié
- Laboratoire d’Astrophysique de Bordeaux, University of Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
- LESIA, Observatoire de Paris, 92195 Meudon, France
| | - L. N. Fletcher
- School of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - M. T. Roman
- School of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK
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10
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Small lightning flashes from shallow electrical storms on Jupiter. Nature 2020; 584:55-58. [PMID: 32760043 DOI: 10.1038/s41586-020-2532-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 04/09/2020] [Indexed: 11/09/2022]
Abstract
Lightning flashes have been observed by a number of missions that visited or flew by Jupiter over the past several decades. Imagery led to a flash rate estimate of about 4 × 10-3 flashes per square kilometre per year (refs. 1,2). The spatial extent of Voyager flashes was estimated to be about 30 kilometres (half-width at half-maximum intensity, HWHM), but the camera was unlikely to have detected the dim outer edges of the flashes, given its weak response to the brightest spectral line of Jovian lightning emission, the 656.3-nanometre Hα line of atomic hydrogen1,3-6. The spatial resolution of some cameras allowed investigators to confirm 22 flashes with HWHM greater than 42 kilometres, and to estimate one with an HWHM of 37 to 45 kilometres (refs. 1,7-9). These flashes, with optical energies comparable to terrestrial 'superbolts'-of (0.02-1.6) × 1010 joules-have been interpreted as tracers of moist convection originating near the 5-bar level of Jupiter's atmosphere (assuming photon scattering from points beneath the clouds)1-3,7,8,10-12. Previous observations of lightning have been limited by camera sensitivity, distance from Jupiter and long exposures (about 680 milliseconds to 85 seconds), meaning that some measurements were probably superimposed flashes reported as one1,2,7,9,10,13. Here we report optical observations of lightning flashes by the Juno spacecraft with energies of approximately 105-108 joules, flash durations as short as 5.4 milliseconds and inter-flash separations of tens of milliseconds, with typical terrestrial energies. The flash rate is about 6.1 × 10-2 flashes per square kilometre per year, more than an order of magnitude greater than hitherto seen. Several flashes are of such small spatial extent that they must originate above the 2-bar level, where there is no liquid water14,15. This implies that multiple mechanisms for generating lightning on Jupiter need to be considered for a full understanding of the planet's atmospheric convection and composition.
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11
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Orton GS, Tabataba-Vakili F, Eichstädt G, Rogers J, Hansen CJ, Momary TW, Ingersoll AP, Brueshaber S, Wong MH, Simon AA, Fletcher LN, Ravine M, Caplinger M, Smith D, Bolton SJ, Levin SM, Sinclair JA, Thepenier C, Nicholson H, Anthony A. A Survey of Small-Scale Waves and Wave-Like Phenomena in Jupiter's Atmosphere Detected by JunoCam. JOURNAL OF GEOPHYSICAL RESEARCH. PLANETS 2020; 125:e2019JE006369. [PMID: 32728504 PMCID: PMC7380317 DOI: 10.1029/2019je006369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 03/05/2020] [Accepted: 03/07/2020] [Indexed: 06/11/2023]
Abstract
In the first 20 orbits of the Juno spacecraft around Jupiter, we have identified a variety of wave-like features in images made by its public-outreach camera, JunoCam. Because of Juno's unprecedented and repeated proximity to Jupiter's cloud tops during its close approaches, JunoCam has detected more wave structures than any previous surveys. Most of the waves appear in long wave packets, oriented east-west and populated by narrow wave crests. Spacing between crests were measured as small as ~30 km, shorter than any previously measured. Some waves are associated with atmospheric features, but others are not ostensibly associated with any visible cloud phenomena and thus may be generated by dynamical forcing below the visible cloud tops. Some waves also appear to be converging, and others appear to be overlapping, possibly at different atmospheric levels. Another type of wave has a series of fronts that appear to be radiating outward from the center of a cyclone. Most of these waves appear within 5° of latitude from the equator, but we have detected waves covering planetocentric latitudes between 20°S and 45°N. The great majority of the waves appear in regions associated with prograde motions of the mean zonal flow. Juno was unable to measure the velocity of wave features to diagnose the wave types due to its close and rapid flybys. However, both by our own upper limits on wave motions and by analogy with previous measurements, we expect that the waves JunoCam detected near the equator are inertia-gravity waves.
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Affiliation(s)
- Glenn S Orton
- Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA
| | | | | | | | | | - Thomas W Momary
- Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA
| | - Andrew P Ingersoll
- Division of Geological and Planetary Sciences, California Institute of Technology Pasadena CA USA
| | - Shawn Brueshaber
- College of Engineering and Applied Sciences, Western Michigan University Kalamazoo MI USA
| | - Michael H Wong
- Department of Astronomy, University of California Berkeley CA USA
- SETI Institute Mountain View CA USA
| | - Amy A Simon
- NASA Goddard Space Flight Center Greenbelt MD USA
| | - Leigh N Fletcher
- Department of Physics and Astronomy, University of Leicester Leicester UK
| | | | | | - Dakota Smith
- National Center for Atmospheric Research Boulder CO USA
| | - Scott J Bolton
- Space Science and Engineering Division, Southwest Research Institute San Antonio TX USA
| | - Steven M Levin
- Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA
| | - James A Sinclair
- Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA
| | - Chloe Thepenier
- Glendale Community College Glendale CA USA
- Now at the University of California Davis CA USA
| | | | - Abigail Anthony
- Golden West College Huntington Beach CA USA
- Now at the University of California Berkeley CA USA
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12
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Lemasquerier D, Facchini G, Favier B, Le Bars M. Remote determination of the shape of Jupiter's vortices from laboratory experiments. NATURE PHYSICS 2020; 16:695-700. [PMID: 32514283 PMCID: PMC7279954 DOI: 10.1038/s41567-020-0833-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 02/10/2020] [Indexed: 06/11/2023]
Abstract
Jupiter's dynamics shapes its cloud patterns but remains largely unknown below this natural observational barrier. Unraveling the underlying three-dimensional flows is thus a primary goal for NASA's ongoing Juno mission that was launched in 2011. Here, we address the dynamics of large Jovian vortices using laboratory experiments complemented by theoretical and numerical analyses. We determine the generic force balance responsible for their three-dimensional pancake-like shape. From this, we define scaling laws for their horizontal and vertical aspect ratios as a function of the ambient rotation, stratification and zonal wind velocity. For the Great Red Spot in particular, our predicted horizontal dimensions agree well with measurements at the cloud level since the Voyager mission in 1979. We additionally predict the Great Red Spot's thickness, inaccessible to direct observation: it has surprisingly remained constant despite the observed horizontal shrinking. Our results now await comparison with upcoming Juno observations.
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Affiliation(s)
- Daphné Lemasquerier
- Aix-Marseille Univ, CNRS, Centrale Marseille, Institut de Recherche
sur les Phénomènes Hors Équilibre, UMR 7342, 49 rue F. Joliot
Curie, 13013 Marseille, France
| | - Giulio Facchini
- Aix-Marseille Univ, CNRS, Centrale Marseille, Institut de Recherche
sur les Phénomènes Hors Équilibre, UMR 7342, 49 rue F. Joliot
Curie, 13013 Marseille, France
| | - Benjamin Favier
- Aix-Marseille Univ, CNRS, Centrale Marseille, Institut de Recherche
sur les Phénomènes Hors Équilibre, UMR 7342, 49 rue F. Joliot
Curie, 13013 Marseille, France
| | - Michael Le Bars
- Aix-Marseille Univ, CNRS, Centrale Marseille, Institut de Recherche
sur les Phénomènes Hors Équilibre, UMR 7342, 49 rue F. Joliot
Curie, 13013 Marseille, France
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13
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Guillot T, Fletcher LN. Revealing giant planet interiors beneath the cloudy veil. Nat Commun 2020; 11:1555. [PMID: 32214104 PMCID: PMC7096516 DOI: 10.1038/s41467-020-15431-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 02/28/2020] [Indexed: 11/16/2022] Open
Abstract
Observations from the Juno and Cassini missions provide essential constraints on the internal structures and compositions of Jupiter and Saturn, resulting in profound revisions of our understanding of the interior and atmospheres of Gas Giant planets. The next step to understand planetary origins in our Solar System requires a mission to their Ice Giant siblings, Uranus and Neptune.
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Affiliation(s)
- Tristan Guillot
- Université Côte d'Azur, OCA, Lagrange CNRS, 06304, Nice, France.
| | - Leigh N Fletcher
- School of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH, UK
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14
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Fletcher LN, Kaspi Y, Guillot T, Showman AP. How Well Do We Understand the Belt/Zone Circulation of Giant Planet Atmospheres? SPACE SCIENCE REVIEWS 2020; 216:30. [PMID: 32214508 PMCID: PMC7067733 DOI: 10.1007/s11214-019-0631-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 12/24/2019] [Indexed: 05/20/2023]
Abstract
The atmospheres of the four giant planets of our Solar System share a common and well-observed characteristic: they each display patterns of planetary banding, with regions of different temperatures, composition, aerosol properties and dynamics separated by strong meridional and vertical gradients in the zonal (i.e., east-west) winds. Remote sensing observations, from both visiting spacecraft and Earth-based astronomical facilities, have revealed the significant variation in environmental conditions from one band to the next. On Jupiter, the reflective white bands of low temperatures, elevated aerosol opacities, and enhancements of quasi-conserved chemical tracers are referred to as 'zones.' Conversely, the darker bands of warmer temperatures, depleted aerosols, and reductions of chemical tracers are known as 'belts.' On Saturn, we define cyclonic belts and anticyclonic zones via their temperature and wind characteristics, although their relation to Saturn's albedo is not as clear as on Jupiter. On distant Uranus and Neptune, the exact relationships between the banded albedo contrasts and the environmental properties is a topic of active study. This review is an attempt to reconcile the observed properties of belts and zones with (i) the meridional overturning inferred from the convergence of eddy angular momentum into the eastward zonal jets at the cloud level on Jupiter and Saturn and the prevalence of moist convective activity in belts; and (ii) the opposing meridional motions inferred from the upper tropospheric temperature structure, which implies decay and dissipation of the zonal jets with altitude above the clouds. These two scenarios suggest meridional circulations in opposing directions, the former suggesting upwelling in belts, the latter suggesting upwelling in zones. Numerical simulations successfully reproduce the former, whereas there is a wealth of observational evidence in support of the latter. This presents an unresolved paradox for our current understanding of the banded structure of giant planet atmospheres, that could be addressed via a multi-tiered vertical structure of "stacked circulation cells," with a natural transition from zonal jet pumping to dissipation as we move from the convectively-unstable mid-troposphere into the stably-stratified upper troposphere.
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Affiliation(s)
- Leigh N. Fletcher
- School of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH UK
| | - Yohai Kaspi
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, 76100 Israel
| | - Tristan Guillot
- Université Côte d’Azur, OCA, Lagrange CNRS, 06304 Nice, France
| | - Adam P. Showman
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721-0092 USA
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15
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Fletcher LN, de Pater I, Orton GS, Hofstadter MD, Irwin PGJ, Roman MT, Toledo D. Ice Giant Circulation Patterns: Implications for Atmospheric Probes. SPACE SCIENCE REVIEWS 2020; 216:21. [PMID: 32165773 PMCID: PMC7040070 DOI: 10.1007/s11214-020-00646-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 02/15/2020] [Indexed: 05/04/2023]
Abstract
Atmospheric circulation patterns derived from multi-spectral remote sensing can serve as a guide for choosing a suitable entry location for a future in situ probe mission to the Ice Giants. Since the Voyager-2 flybys in the 1980s, three decades of observations from ground- and space-based observatories have generated a picture of Ice Giant circulation that is complex, perplexing, and altogether unlike that seen on the Gas Giants. This review seeks to reconcile the various competing circulation patterns from an observational perspective, accounting for spatially-resolved measurements of: zonal albedo contrasts and banded appearances; cloud-tracked zonal winds; temperature and para-H2 measurements above the condensate clouds; and equator-to-pole contrasts in condensable volatiles (methane, ammonia, and hydrogen sulphide) in the deeper troposphere. These observations identify three distinct latitude domains: an equatorial domain of deep upwelling and upper-tropospheric subsidence, potentially bounded by peaks in the retrograde zonal jet and analogous to Jovian cyclonic belts; a mid-latitude transitional domain of upper-tropospheric upwelling, vigorous cloud activity, analogous to Jovian anticyclonic zones; and a polar domain of strong subsidence, volatile depletion, and small-scale (and potentially seasonally-variable) convective activity. Taken together, the multi-wavelength observations suggest a tiered structure of stacked circulation cells (at least two in the troposphere and one in the stratosphere), potentially separated in the vertical by (i) strong molecular weight gradients associated with cloud condensation, and by (ii) transitions from a thermally-direct circulation regime at depth to a wave- and radiative-driven circulation regime at high altitude. The inferred circulation can be tested in the coming decade by 3D numerical simulations of the atmosphere, and by observations from future world-class facilities. The carrier spacecraft for any probe entry mission must ultimately carry a suite of remote-sensing instruments capable of fully constraining the atmospheric motions at the probe descent location.
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Affiliation(s)
- Leigh N. Fletcher
- School of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH UK
| | - Imke de Pater
- Department of Astronomy, University of California, 501 Campbell Hall, Berkeley, CA 94720 USA
| | - Glenn S. Orton
- Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 USA
| | | | - Patrick G. J. Irwin
- Atmospheric, Oceanic and Planetary Physics, University of Oxford, Parks Road, Oxford, OX1 3PU UK
| | - Michael T. Roman
- School of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH UK
| | - Daniel Toledo
- Atmospheric, Oceanic and Planetary Physics, University of Oxford, Parks Road, Oxford, OX1 3PU UK
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16
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Fletcher LN, de Pater I, Orton GS, Hofstadter MD, Irwin PGJ, Roman MT, Toledo D. Ice Giant Circulation Patterns: Implications for Atmospheric Probes. SPACE SCIENCE REVIEWS 2020. [PMID: 32165773 DOI: 10.1007/s11214-019-0619-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Atmospheric circulation patterns derived from multi-spectral remote sensing can serve as a guide for choosing a suitable entry location for a future in situ probe mission to the Ice Giants. Since the Voyager-2 flybys in the 1980s, three decades of observations from ground- and space-based observatories have generated a picture of Ice Giant circulation that is complex, perplexing, and altogether unlike that seen on the Gas Giants. This review seeks to reconcile the various competing circulation patterns from an observational perspective, accounting for spatially-resolved measurements of: zonal albedo contrasts and banded appearances; cloud-tracked zonal winds; temperature and para-H2 measurements above the condensate clouds; and equator-to-pole contrasts in condensable volatiles (methane, ammonia, and hydrogen sulphide) in the deeper troposphere. These observations identify three distinct latitude domains: an equatorial domain of deep upwelling and upper-tropospheric subsidence, potentially bounded by peaks in the retrograde zonal jet and analogous to Jovian cyclonic belts; a mid-latitude transitional domain of upper-tropospheric upwelling, vigorous cloud activity, analogous to Jovian anticyclonic zones; and a polar domain of strong subsidence, volatile depletion, and small-scale (and potentially seasonally-variable) convective activity. Taken together, the multi-wavelength observations suggest a tiered structure of stacked circulation cells (at least two in the troposphere and one in the stratosphere), potentially separated in the vertical by (i) strong molecular weight gradients associated with cloud condensation, and by (ii) transitions from a thermally-direct circulation regime at depth to a wave- and radiative-driven circulation regime at high altitude. The inferred circulation can be tested in the coming decade by 3D numerical simulations of the atmosphere, and by observations from future world-class facilities. The carrier spacecraft for any probe entry mission must ultimately carry a suite of remote-sensing instruments capable of fully constraining the atmospheric motions at the probe descent location.
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Affiliation(s)
- Leigh N Fletcher
- 1School of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH UK
| | - Imke de Pater
- 3Department of Astronomy, University of California, 501 Campbell Hall, Berkeley, CA 94720 USA
| | - Glenn S Orton
- 2Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 USA
| | - Mark D Hofstadter
- 2Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 USA
| | - Patrick G J Irwin
- 4Atmospheric, Oceanic and Planetary Physics, University of Oxford, Parks Road, Oxford, OX1 3PU UK
| | - Michael T Roman
- 1School of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH UK
| | - Daniel Toledo
- 4Atmospheric, Oceanic and Planetary Physics, University of Oxford, Parks Road, Oxford, OX1 3PU UK
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17
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18
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Kaspi Y, Galanti E, Hubbard WB, Stevenson DJ, Bolton SJ, Iess L, Guillot T, Bloxham J, Connerney JEP, Cao H, Durante D, Folkner WM, Helled R, Ingersoll AP, Levin SM, Lunine JI, Miguel Y, Militzer B, Parisi M, Wahl SM. Jupiter's atmospheric jet streams extend thousands of kilometres deep. Nature 2018. [PMID: 29516995 DOI: 10.1038/nature25793] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The depth to which Jupiter's observed east-west jet streams extend has been a long-standing question. Resolving this puzzle has been a primary goal for the Juno spacecraft, which has been in orbit around the gas giant since July 2016. Juno's gravitational measurements have revealed that Jupiter's gravitational field is north-south asymmetric, which is a signature of the planet's atmospheric and interior flows. Here we report that the measured odd gravitational harmonics J3, J5, J7 and J9 indicate that the observed jet streams, as they appear at the cloud level, extend down to depths of thousands of kilometres beneath the cloud level, probably to the region of magnetic dissipation at a depth of about 3,000 kilometres. By inverting the measured gravity values into a wind field, we calculate the most likely vertical profile of the deep atmospheric and interior flow, and the latitudinal dependence of its depth. Furthermore, the even gravity harmonics J8 and J10 resulting from this flow profile also match the measurements, when taking into account the contribution of the interior structure. These results indicate that the mass of the dynamical atmosphere is about one per cent of Jupiter's total mass.
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Affiliation(s)
- Y Kaspi
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - E Galanti
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - W B Hubbard
- Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85721, USA
| | - D J Stevenson
- Divison of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA
| | - S J Bolton
- Southwest Research Institute, San Antonio, Texas 78238, USA
| | - L Iess
- Department of Mechanical and Aerospace Engineering, Sapienza Universita di Roma, 00184 Rome, Italy
| | - T Guillot
- Université Côte d'Azur, OCA, Lagrange CNRS, 06304 Nice, France
| | - J Bloxham
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - J E P Connerney
- Space Research Corporation, Annapolis, Maryland 21403, USA.,NASA/GSFC, Greenbelt, Maryland 20771, USA
| | - H Cao
- Divison of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA.,Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - D Durante
- Department of Mechanical and Aerospace Engineering, Sapienza Universita di Roma, 00184 Rome, Italy
| | - W M Folkner
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - R Helled
- Institute for Computational Science, Center for Theoretical Astrophysics and Cosmology, University of Zurich, 8057 Zurich, Switzerland
| | - A P Ingersoll
- Divison of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA
| | - S M Levin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - J I Lunine
- Department of Astronomy, Cornell University, Ithaca, New York 14853, USA
| | - Y Miguel
- Université Côte d'Azur, OCA, Lagrange CNRS, 06304 Nice, France.,Leiden Observatory, University of Leiden, Leiden, The Netherlands
| | - B Militzer
- Department of Earth and Planetray Science, University of California, Berkeley, California 94720, USA
| | - M Parisi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - S M Wahl
- Department of Earth and Planetray Science, University of California, Berkeley, California 94720, USA
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19
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Brown S, Janssen M, Adumitroaie V, Atreya S, Bolton S, Gulkis S, Ingersoll A, Levin S, Li C, Li L, Lunine J, Misra S, Orton G, Steffes P, Tabataba-Vakili F, Kolmašová I, Imai M, Santolík O, Kurth W, Hospodarsky G, Gurnett D, Connerney J. Prevalent lightning sferics at 600 megahertz near Jupiter's poles. Nature 2018; 558:87-90. [PMID: 29875484 DOI: 10.1038/s41586-018-0156-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 03/14/2018] [Indexed: 11/09/2022]
Abstract
Lightning has been detected on Jupiter by all visiting spacecraft through night-side optical imaging and whistler (lightning-generated radio waves) signatures1-6. Jovian lightning is thought to be generated in the mixed-phase (liquid-ice) region of convective water clouds through a charge-separation process between condensed liquid water and water-ice particles, similar to that of terrestrial (cloud-to-cloud) lightning7-9. Unlike terrestrial lightning, which emits broadly over the radio spectrum up to gigahertz frequencies10,11, lightning on Jupiter has been detected only at kilohertz frequencies, despite a search for signals in the megahertz range 12 . Strong ionospheric attenuation or a lightning discharge much slower than that on Earth have been suggested as possible explanations for this discrepancy13,14. Here we report observations of Jovian lightning sferics (broadband electromagnetic impulses) at 600 megahertz from the Microwave Radiometer 15 onboard the Juno spacecraft. These detections imply that Jovian lightning discharges are not distinct from terrestrial lightning, as previously thought. In the first eight orbits of Juno, we detected 377 lightning sferics from pole to pole. We found lightning to be prevalent in the polar regions, absent near the equator, and most frequent in the northern hemisphere, at latitudes higher than 40 degrees north. Because the distribution of lightning is a proxy for moist convective activity, which is thought to be an important source of outward energy transport from the interior of the planet16,17, increased convection towards the poles could indicate an outward internal heat flux that is preferentially weighted towards the poles9,16,18. The distribution of moist convection is important for understanding the composition, general circulation and energy transport on Jupiter.
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Affiliation(s)
- Shannon Brown
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
| | - Michael Janssen
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Virgil Adumitroaie
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Sushil Atreya
- Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Scott Bolton
- Southwest Research Institute, San Antonio, TX, USA
| | - Samuel Gulkis
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | - Steven Levin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Cheng Li
- California Institute of Technology, Pasadena, CA, USA
| | - Liming Li
- Department of Physics, University of Houston, Houston, TX, USA
| | - Jonathan Lunine
- Department of Astronomy, Cornell University, Ithaca, NY, USA
| | - Sidharth Misra
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Glenn Orton
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Paul Steffes
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | | | - Ivana Kolmašová
- Department of Space Physics, Institute of Atmospheric Physics, The Czech Academy of Sciences, Prague, Czechia.,Faculty of Mathematics and Physics, Charles University, Prague, Czechia
| | - Masafumi Imai
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA
| | - Ondřej Santolík
- Department of Space Physics, Institute of Atmospheric Physics, The Czech Academy of Sciences, Prague, Czechia.,Faculty of Mathematics and Physics, Charles University, Prague, Czechia
| | - William Kurth
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA
| | - George Hospodarsky
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA
| | - Donald Gurnett
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA
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20
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Bolton SJ, Adriani A, Adumitroaie V, Allison M, Anderson J, Atreya S, Bloxham J, Brown S, Connerney JEP, DeJong E, Folkner W, Gautier D, Grassi D, Gulkis S, Guillot T, Hansen C, Hubbard WB, Iess L, Ingersoll A, Janssen M, Jorgensen J, Kaspi Y, Levin SM, Li C, Lunine J, Miguel Y, Mura A, Orton G, Owen T, Ravine M, Smith E, Steffes P, Stone E, Stevenson D, Thorne R, Waite J, Durante D, Ebert RW, Greathouse TK, Hue V, Parisi M, Szalay JR, Wilson R. Jupiter's interior and deep atmosphere: The initial pole-to-pole passes with the Juno spacecraft. Science 2018; 356:821-825. [PMID: 28546206 DOI: 10.1126/science.aal2108] [Citation(s) in RCA: 186] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 05/01/2017] [Indexed: 11/02/2022]
Abstract
On 27 August 2016, the Juno spacecraft acquired science observations of Jupiter, passing less than 5000 kilometers above the equatorial cloud tops. Images of Jupiter's poles show a chaotic scene, unlike Saturn's poles. Microwave sounding reveals weather features at pressures deeper than 100 bars, dominated by an ammonia-rich, narrow low-latitude plume resembling a deeper, wider version of Earth's Hadley cell. Near-infrared mapping reveals the relative humidity within prominent downwelling regions. Juno's measured gravity field differs substantially from the last available estimate and is one order of magnitude more precise. This has implications for the distribution of heavy elements in the interior, including the existence and mass of Jupiter's core. The observed magnetic field exhibits smaller spatial variations than expected, indicative of a rich harmonic content.
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Affiliation(s)
- S J Bolton
- Southwest Research Institute, San Antonio, TX 78238, USA.
| | - A Adriani
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, 00133 Rome, Italy
| | - V Adumitroaie
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - M Allison
- Goddard Institute for Space Studies, New York, NY 10025, USA
| | - J Anderson
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - S Atreya
- University of Michigan, Ann Arbor, MI 48109, USA
| | - J Bloxham
- Harvard University, Cambridge, MA 02138, USA
| | - S Brown
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - J E P Connerney
- Space Research Corporation, Annapolis, MD 21403, USA.,NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - E DeJong
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - W Folkner
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - D Gautier
- Laboratoire d'Études Spatiales et d'Instrumentation en Astrophysique, Observatoire de Paris, 92195 Meudon, France
| | - D Grassi
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, 00133 Rome, Italy
| | - S Gulkis
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - T Guillot
- Université Côte d'Azur, Observatoire de la Côte d'Azur, Laboratoire Lagrange CNRS, 06304 Nice, France
| | - C Hansen
- Planetary Science Institute, Tucson, AZ 85719, USA
| | - W B Hubbard
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA
| | - L Iess
- Sapienza University of Rome, 00185 Rome, Italy
| | - A Ingersoll
- California Institute of Technology, Pasadena, CA 91125, USA
| | - M Janssen
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - J Jorgensen
- National Space Institute, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Y Kaspi
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - S M Levin
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - C Li
- California Institute of Technology, Pasadena, CA 91125, USA
| | - J Lunine
- Cornell University, Ithaca, NY 14853, USA
| | - Y Miguel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, Laboratoire Lagrange CNRS, 06304 Nice, France
| | - A Mura
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, 00133 Rome, Italy
| | - G Orton
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - T Owen
- Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - M Ravine
- Malin Space Science Systems, San Diego, CA 92121, USA
| | - E Smith
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - P Steffes
- Center for Space Technology and Research, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - E Stone
- California Institute of Technology, Pasadena, CA 91125, USA
| | - D Stevenson
- California Institute of Technology, Pasadena, CA 91125, USA
| | - R Thorne
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA 90095, USA
| | - J Waite
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - D Durante
- Sapienza University of Rome, 00185 Rome, Italy
| | - R W Ebert
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - T K Greathouse
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - V Hue
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - M Parisi
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - J R Szalay
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - R Wilson
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA
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21
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Ingersoll AP, Adumitroaie V, Allison MD, Atreya S, Bellotti AA, Bolton SJ, Brown ST, Gulkis S, Janssen MA, Levin SM, Li C, Li L, Lunine JI, Orton GS, Oyafuso FA, Steffes PG. Implications of the ammonia distribution on Jupiter from 1 to 100 bars as measured by the Juno microwave radiometer. GEOPHYSICAL RESEARCH LETTERS 2017; 44:7676-7685. [PMID: 33100420 PMCID: PMC7580824 DOI: 10.1002/2017gl074277] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The latitude-altitude map of ammonia mixing ratio shows an ammonia-rich zone at 0-5°N, with mixing ratios of 320-340 ppm, extending from 40-60 bars up to the ammonia cloud base at 0.7 bars. Ammonia-poor air occupies a belt from 5-20°N. We argue that downdrafts as well as updrafts are needed in the 0-5°N zone to balance the upward ammonia flux. Outside the 0-20°N region, the belt-zone signature is weaker. At latitudes out to ±40°, there is an ammonia-rich layer from cloud base down to 2 bars which we argue is caused by falling precipitation. Below, there is an ammonia-poor layer with a minimum at 6 bars. Unanswered questions include how the ammonia-poor layer is maintained, why the belt-zone structure is barely evident in the ammonia distribution outside 0-20°N, and how the internal heat is transported through the ammonia-poor layer to the ammonia cloud base.
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Affiliation(s)
- Andrew P Ingersoll
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Virgil Adumitroaie
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | | | - Sushil Atreya
- Climate and Space Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Amadeo A Bellotti
- Center for Space Technology and Research, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Scott J Bolton
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - Shannon T Brown
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Samuel Gulkis
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Michael A Janssen
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Steven M Levin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Cheng Li
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Liming Li
- Department of Physics, University of Houston, Houston, TX 77004, USA
| | | | - Glenn S Orton
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Fabiano A Oyafuso
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Paul G Steffes
- Center for Space Technology and Research, Georgia Institute of Technology, Atlanta, GA 30332, USA
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22
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Witze A. Jupiter’s secrets revealed by NASA probe. Nature 2017. [DOI: 10.1038/nature.2017.22027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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