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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 Sci Rev 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Irwin PGJ, Teanby NA, Fletcher LN, Toledo D, Orton GS, Wong MH, Roman MT, Pérez‐Hoyos S, James A, Dobinson J. Hazy Blue Worlds: A Holistic Aerosol Model for Uranus and Neptune, Including Dark Spots. J Geophys Res Planets 2022; 127:e2022JE007189. [PMID: 35865671 PMCID: PMC9286428 DOI: 10.1029/2022je007189] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 04/28/2022] [Accepted: 05/16/2022] [Indexed: 06/15/2023]
Abstract
We present a reanalysis (using the Minnaert limb-darkening approximation) of visible/near-infrared (0.3-2.5 μm) observations of Uranus and Neptune made by several instruments. We find a common model of the vertical aerosol distribution i.e., consistent with the observed reflectivity spectra of both planets, consisting of: (a) a deep aerosol layer with a base pressure >5-7 bar, assumed to be composed of a mixture of H2S ice and photochemical haze; (b) a layer of photochemical haze/ice, coincident with a layer of high static stability at the methane condensation level at 1-2 bar; and (c) an extended layer of photochemical haze, likely mostly of the same composition as the 1-2-bar layer, extending from this level up through to the stratosphere, where the photochemical haze particles are thought to be produced. For Neptune, we find that we also need to add a thin layer of micron-sized methane ice particles at ∼0.2 bar to explain the enhanced reflection at longer methane-absorbing wavelengths. We suggest that methane condensing onto the haze particles at the base of the 1-2-bar aerosol layer forms ice/haze particles that grow very quickly to large size and immediately "snow out" (as predicted by Carlson et al. (1988), https://doi.org/10.1175/1520-0469(1988)045<2066:CMOTGP>2.0.CO;2), re-evaporating at deeper levels to release their core haze particles to act as condensation nuclei for H2S ice formation. In addition, we find that the spectral characteristics of "dark spots", such as the Voyager-2/ISS Great Dark Spot and the HST/WFC3 NDS-2018, are well modelled by a darkening or possibly clearing of the deep aerosol layer only.
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Affiliation(s)
| | - N. A. Teanby
- School of Earth SciencesUniversity of BristolBristolUK
| | - L. N. Fletcher
- School of Physics & AstronomyUniversity of LeicesterLeicesterUK
| | - D. Toledo
- Instituto Nacional de Técnica Aeroespacial (INTA)MadridSpain
| | - G. S. Orton
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - M. H. Wong
- Center for Integrative Planetary ScienceUniversity of CaliforniaBerkeleyCAUSA
| | - M. T. Roman
- School of Physics & AstronomyUniversity of LeicesterLeicesterUK
| | | | - A. James
- Department of PhysicsUniversity of OxfordOxfordUK
| | - J. Dobinson
- Department of PhysicsUniversity of OxfordOxfordUK
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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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Moses JI, Cavalié T, Fletcher LN, Roman MT. Atmospheric chemistry on Uranus and Neptune. Philos Trans A Math Phys Eng Sci 2020; 378:20190477. [PMID: 33161866 PMCID: PMC7658780 DOI: 10.1098/rsta.2019.0477] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Fletcher LN, de Pater I, Orton GS, Hofstadter MD, Irwin PGJ, Roman MT, Toledo D. Ice Giant Circulation Patterns: Implications for Atmospheric Probes. Space Sci Rev 2020. [PMID: 32165773 DOI: 10.1007/s11214-019-0619-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Fletcher LN, de Pater I, Orton GS, Hofstadter MD, Irwin PGJ, Roman MT, Toledo D. Ice Giant Circulation Patterns: Implications for Atmospheric Probes. Space Sci Rev 2020; 216:21. [PMID: 32165773 PMCID: PMC7040070 DOI: 10.1007/s11214-020-00646-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Moore L, Melin H, O'Donoghue J, Stallard TS, Moses JI, Galand M, Miller S, Schmidt CA. Modelling H 3+ in planetary atmospheres: effects of vertical gradients on observed quantities. Philos Trans A Math Phys Eng Sci 2019; 377:20190067. [PMID: 31378180 PMCID: PMC6710898 DOI: 10.1098/rsta.2019.0067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/07/2019] [Indexed: 05/20/2023]
Abstract
Since its detection in the aurorae of Jupiter approximately 30 years ago, the H3+ ion has served as an invaluable probe of giant planet upper atmospheres. However, the vast majority of monitoring of planetary H3+ radiation has followed from observations that rely on deriving parameters from column-integrated paths through the emitting layer. Here, we investigate the effects of density and temperature gradients along such paths on the measured H3+ spectrum and its resulting interpretation. In a non-isothermal atmosphere, H3+ column densities retrieved from such observations are found to represent a lower limit, reduced by 20% or more from the true atmospheric value. Global simulations of Uranus' ionosphere reveal that measured H3+ temperature variations are often attributable to well-understood solar zenith angle effects rather than indications of real atmospheric variability. Finally, based on these insights, a preliminary method of deriving vertical temperature structure is demonstrated at Jupiter using model reproductions of electron density and H3+ measurements. The sheer diversity and uncertainty of conditions in planetary atmospheres prohibits this work from providing blanket quantitative correction factors; nonetheless, we illustrate a few simple ways in which the already formidable utility of H3+ observations in understanding planetary atmospheres can be enhanced. This article is part of a discussion meeting issue 'Advances in hydrogen molecular ions: H3+, H5+ and beyond'.
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Affiliation(s)
- L. Moore
- Boston University, Boston, MA, USA
| | - H. Melin
- University of Leicester, Leicester, UK
| | - J. O'Donoghue
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | | | | | - M. Galand
- Department of Physics, Imperial College London, London, UK
| | - S. Miller
- University College London, London, UK
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Abstract
A time-variable 1D photochemical model is used to study the distribution of stratospheric hydrocarbons as a function of altitude, latitude, and season on Uranus and Neptune. The results for Neptune indicate that in the absence of stratospheric circulation or other meridional transport processes, the hydrocarbon abundances exhibit strong seasonal and meridional variations in the upper stratosphere, but that these variations become increasingly damped with depth due to increasing dynamical and chemical time scales. At high altitudes, hydrocarbon mixing ratios are typically largest where the solar insolation is the greatest, leading to strong hemispheric dichotomies between the summer-to-fall hemisphere and winter-to-spring hemisphere. At mbar pressures and deeper, slower chemistry and diffusion lead to latitude variations that become more symmetric about the equator. On Uranus, the stagnant, poorly mixed stratosphere confines methane and its photochemical products to higher pressures, where chemistry and diffusion time scales remain large. Seasonal variations in hydrocarbons are therefore predicted to be more muted on Uranus, despite the planet's very large obliquity. Radiative-transfer simulations demonstrate that latitude variations in hydrocarbons on both planets are potentially observable with future JWST mid-infrared spectral imaging. Our seasonal model predictions for Neptune compare well with retrieved C2H2 and C2H6 abundances from spatially resolved ground-based observations (no such observations currently exist for Uranus), suggesting that stratospheric circulation - which was not included in these models - may have little influence on the large-scale meridional hydrocarbon distributions on Neptune, unlike the situation on Jupiter and Saturn.
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Affiliation(s)
- Julianne I Moses
- Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA
| | - Leigh N Fletcher
- Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | | | - Glenn S Orton
- Jet Propulsion Laboratory, MS 183-501, Pasadena, CA 91109, USA
| | - Vincent Hue
- Southwest Research Institute, San Antonio, TX 78228, USA
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9
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Abstract
Ablation of interplanetary dust supplies oxygen to the upper atmospheres of Jupiter, Saturn, Uranus, and Neptune. Using recent dynamical model predictions for the dust influx rates to the giant planets (Poppe, A.R. et al. [2016], Icarus 264, 369), we calculate the ablation profiles and investigate the subsequent coupled oxygen-hydrocarbon neutral photochemistry in the stratospheres of these planets. We find that dust grains from the Edgeworth-Kuiper Belt, Jupiter-family comets, and Oort-cloud comets supply an effective oxygen influx rate of1.0 - 0.7 + 2.2 × 10 7 O atoms cm-2 s-1 to Jupiter,7.4 - 5.1 + 16 × 10 4 cm-2 s-1 to Saturn,8.9 - 6.1 + 19 × 10 4 cm-2 s-1 to Uranus, and7.5 - 5.1 + 16 × 10 5 cm-2 s-1 to Neptune. The fate of the ablated oxygen depends in part on the molecular/atomic form of the initially delivered products, and on the altitude at which it was deposited. The dominant stratospheric products are CO, H2O, and CO2, which are relatively stable photochemically. Model-data comparisons suggest that interplanetary dust grains deliver an important component of the external oxygen to Jupiter and Uranus but fall far short of the amount needed to explain the CO abundance currently seen in the middle stratospheres of Saturn and Neptune. Our results are consistent with the theory that all of the giant planets have experienced large cometary impacts within the last few hundred years. Our results also suggest that the low background H2O abundance in Jupiter's stratosphere is indicative of effective conversion of meteoric oxygen to CO during or immediately after the ablation process - photochemistry alone cannot efficiently convert the H2O into CO on the giant planets.
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Affiliation(s)
- Julianne I Moses
- Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA
| | - Andrew R Poppe
- Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720, USA
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Affiliation(s)
- Rommel B. Viana
- Departamento de Química e Física Molecular, Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, Brazil
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Mandt K, Mousis O, Marty B, Cavalié T, Harris W, Hartogh P, Willacy K. Constraints from Comets on the Formation and Volatile Acquisition of the Planets and Satellites. Space Sci Rev 2015; 197:297-342. [PMID: 31105346 PMCID: PMC6525011 DOI: 10.1007/s11214-015-0161-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Comets play a dual role in understanding the formation and evolution of the solar system. First, the composition of comets provides information about the origin of the giant planets and their moons because comets formed early and their composition is not expected to have evolved significantly since formation. They, therefore serve as a record of conditions during the early stages of solar system formation. Once comets had formed, their orbits were perturbed allowing them to travel into the inner solar system and impact the planets. In this way they contributed to the volatile inventory of planetary atmospheres. We review here how knowledge of comet composition up to the time of the Rosetta mission has contributed to understanding the formation processes of the giant planets, their moons and small icy bodies in the solar system. We also discuss how comets contributed to the volatile inventories of the giant and terrestrial planets.
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Affiliation(s)
- K.E. Mandt
- Southwest Research Institute, San Antonio, TX, USA
| | - O. Mousis
- Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388, Marseille, France
| | - B. Marty
- CRPG-CNRS, Nancy-Université, Vandoeuvre-lès-Nancy, France
| | - T. Cavalié
- Max Planck Institute for Solar System Research, Göttingen, Germany
| | - W. Harris
- University of Arizona, Tucson, AZ, USA
| | - P. Hartogh
- Max Planck Institute for Solar System Research, Göttingen, Germany
| | - K. Willacy
- Jet Propulsion Laboratory, Pasadena, CA, USA
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Moses JI, Armstrong ES, Fletcher LN, Friedson AJ, Irwin PGJ, Sinclair JA, Hesman BE. Evolution of Stratospheric Chemistry in the Saturn Storm Beacon Region. Icarus 2015; 261:149-168. [PMID: 30842685 PMCID: PMC6398963 DOI: 10.1016/j.icarus.2015.08.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The giant northern-hemisphere storm that erupted on Saturn in December 2010 triggered significant changes in stratospheric temperatures and species abundances that persisted for more than a year after the original outburst. The stratospheric regions affected by the storm have been nicknamed "beacons" due to their prominent infrared-emission signatures (Fletcher, L.N. et al. [2011]. Science 332, 1413). The two beacon regions that were present initially merged in April 2011 to form a single, large, anticyclonic vortex (Fletcher, L.N. et al. [2012]. Icarus 221, 560). We model the expected photochemical evolution of the stratospheric constituents in the beacons from the initial storm onset through the merger and on out to March 2012. The results are compared with longitudinally resolved Cassini/CIRS spectra from May 2011. If we ignore potential changes due to vertical winds within the beacon, we find that C2H2, C2H6, and C3H8 remain unaffected by the increased stratospheric temperatures in the beacon, the abundance of the shorter-lived CH3C2H decreases, and the abundance of C2H4 increases significantly due to the elevated temperatures, the latter most notably in a secondary mixing-ratio peak located near mbar pressures. The C4H2 abundance in the model decreases by a factor of a few in the 0.01-10 mbar region but has a significant increase in the 10-30 mbar region due to evaporation of the previously condensed phase. The column abundances of C6H6 and H2O above ~30 mbar also increase due to aerosol evaporation. Model-data comparisons show that models that consider temperature changes alone underpredict the abundance of C2H x species by a factor of 2-7 in the beacon core in May 2011, suggesting that other processes not considered by the models, such as downwelling winds in the vortex, are affecting the species profiles. Additional calculations indicate that downwelling winds of order -10 cm s -1 near ~0.1 mbar need to be included in the photochemical models in order to explain the inferred C2H x abundances in the beacon core, indicating that both strong subsiding winds and chemistry at elevated temperatures are affecting the vertical profiles of atmospheric constituents in the beacon. We (i) discuss the general chemical behavior of stratospheric species in the beacon region, (ii) demonstrate how the evolving beacon environment affects the species vertical profiles and emission characteristics (both with and without the presence of vertical winds), (iii) make predictions with respect to compositional changes that can be tested against Cassini and Herschel data, and higher-spectral-resolution ground-based observations of the beacon region, and (iv) discuss future measurements and modeling that could further our understanding of the dynamical origin, evolution, and chemical processing within these unexpected stratospheric vortices that were generated after the 2010 convective event.
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Affiliation(s)
- Julianne I Moses
- Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA
| | - Eleanor S Armstrong
- Atmospheric, Oceanic & Planetary Physics, Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK
| | - Leigh N Fletcher
- Atmospheric, Oceanic & Planetary Physics, Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK
| | | | - Patrick G J Irwin
- Atmospheric, Oceanic & Planetary Physics, Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK
| | - James A Sinclair
- Atmospheric, Oceanic & Planetary Physics, Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK
| | - Brigette E Hesman
- Department of Astronomy, University of Maryland, College Park, MD, 20742, USA
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Moore L, Mueller-Wodarg I, Galand M, Kliore A, Mendillo M. Latitudinal variations in Saturn's ionosphere: Cassini measurements and model comparisons. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010ja015692] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [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)
- Luke Moore
- Center for Space Physics; Boston University; Boston Massachusetts USA
| | | | - Marina Galand
- Department of Physics; Imperial College London; London UK
| | - Arvydas Kliore
- Radio Science Systems; Jet Propulsion Laboratory; Pasadena California USA
| | - Michael Mendillo
- Center for Space Physics; Boston University; Boston Massachusetts USA
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Taylor SE, Goddard A, Blitz MA, Cleary PA, Heard DE. Pulsed Laval nozzle study of the kinetics of OH with unsaturated hydrocarbons at very low temperatures. Phys Chem Chem Phys 2008; 10:422-37. [DOI: 10.1039/b711411g] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Affiliation(s)
- A. Glocer
- Center for Space Environment Modeling; University of Michigan; Ann Arbor Michigan USA
| | - T. I. Gombosi
- Center for Space Environment Modeling; University of Michigan; Ann Arbor Michigan USA
| | - G. Toth
- Center for Space Environment Modeling; University of Michigan; Ann Arbor Michigan USA
| | - K. C. Hansen
- Center for Space Environment Modeling; University of Michigan; Ann Arbor Michigan USA
| | - A. J. Ridley
- Center for Space Environment Modeling; University of Michigan; Ann Arbor Michigan USA
| | - A. Nagy
- Center for Space Environment Modeling; University of Michigan; Ann Arbor Michigan USA
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Hébrard E, Dobrijevic M, Bénilan Y, Raulin F. Photochemical kinetics uncertainties in modeling Titan’s atmosphere: A review. Journal of Photochemistry and Photobiology C: Photochemistry Reviews 2006. [DOI: 10.1016/j.jphotochemrev.2006.12.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Moses JI, Fouchet T, Bézard B, Gladstone GR, Lellouch E, Feuchtgruber H. Photochemistry and diffusion in Jupiter's stratosphere: Constraints from ISO observations and comparisons with other giant planets. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005je002411] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.4] [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. I. Moses
- Lunar and Planetary Institute; Houston Texas USA
| | - T. Fouchet
- LESIA; Observatoire de Paris; Meudon France
- Université Paris 6; Paris France
| | - B. Bézard
- LESIA; Observatoire de Paris; Meudon France
| | - G. R. Gladstone
- Space Sciences Department; Southwest Research Institute; San Antonio Texas USA
| | | | - H. Feuchtgruber
- Max-Planck-Institut für Extraterrestrische Physik; Garching Germany
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Lang Q, Cheng IF, Wai CM, Paszczynski A, Crawford RL, Barnes B, Anderson TJ, Wells R, Corti G, Allenbach L, Erwin DP, Assefi T, Mojarradi M. Supercritical fluid extraction and high-performance liquid chromatography-diode array-electrochemical detection of signature redox compounds from sand and soil samples. Anal Biochem 2002; 301:225-34. [PMID: 11814293 DOI: 10.1006/abio.2001.5502] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [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: 11/22/2022]
Abstract
A supercritical fluid extraction procedure and a chromatographic separation/detection method were developed for the detection of Earth-based microorganisms. After microbes in a sand or a soil sample were hydrolyzed in a diluted NH(4)OH/acetone solution, several redox compounds from bacteria could be effectively extracted with trimethylamine-modified supercritical CO(2) at 35 degrees C and 300 atm. These signature redox-active compounds were separated by a reversed-phase HPLC column in an ion-pair mode and then monitored with a diode array detector and an electrochemical detector. The analytical results demonstrated the feasibility of using the reported techniques to detect the chemical signature of life in barren desert sand samples.
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Affiliation(s)
- Qingyong Lang
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844, USA
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Grebowsky JM, Moses JI, Pesnell WD. Meteoric material—an important component of planetary atmospheres. Atmospheres in the Solar System: Comparative Aeronomy 2002. [DOI: 10.1029/130gm15] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Atreya SK, Wong MH, Owen TC, Mahaffy PR, Niemann HB, de Pater I, Drossart P, Encrenaz TH. A comparison of the atmospheres of Jupiter and Saturn: deep atmospheric composition, cloud structure, vertical mixing, and origin. Planet Space Sci 1999; 47:1243-1262. [PMID: 11543193 DOI: 10.1016/s0032-0633(99)00047-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We present our current understanding of the composition, vertical mixing, cloud structure and the origin of the atmospheres of Jupiter and Saturn. Available observations point to a much more vigorous vertical mixing in Saturn's middle-upper atmosphere than in Jupiter's. The nearly cloud-free nature of the Galileo probe entry site, a 5-micron hotspot, is consistent with the depletion of condensable volatiles to great depths, which is attributed to local meteorology. Somewhat similar depletion of water may be present in the 5-micron bright regions of Saturn also. The supersolar abundances of heavy elements, particularly C and S in Jupiter's atmosphere and C in Saturn's, as well as the progressive increase of C from Jupiter to Saturn and beyond, tend to support the icy planetesimal model of the formation of the giant planets and their atmospheres. However, much work remains to be done, especially in the area of laboratory studies, including identification of possible new microwave absorbers, and modelling, in order to resolve the controversy surrounding the large discrepancy between Jupiter's global ammonia abundance, hence the nitrogen elemental ratio, derived from the earth-based microwave observations and that inferred from the analysis of the Galileo probe-orbiter radio attenuation data for the hotspot. We look forward to the observations from Cassini-Huygens spacecraft which are expected to result not only in a rich harvest of information for Saturn, but a better understanding of the formation of the giant planets and their atmospheres when these data are combined with those that exist for Jupiter.
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Affiliation(s)
- S K Atreya
- Department of Atmospheric, Oceanic and Space Sciences, The University of Michigan, Ann Arbor 48109-2143, USA.
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Abstract
An off-limb scan of Callisto was conducted by the Galileo near-infrared mapping spectrometer to search for a carbon dioxide atmosphere. Airglow in the carbon dioxide nu3 band was observed up to 100 kilometers above the surface and indicates the presence of a tenuous carbon dioxide atmosphere with surface pressure of 7.5 x 10(-12) bar and a temperature of about 150 kelvin, close to the surface temperature. A lifetime on the order of 4 years is suggested, based on photoionization and magnetospheric sweeping. Either the atmosphere is transient and was formed recently or some process is currently supplying carbon dioxide to the atmosphere.
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Affiliation(s)
- R W Carlson
- Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 183-601, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
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Affiliation(s)
- B Bézard
- Départment de Recherche Spatiale, Observatoire de Paris-Meudon, France.
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Niemann HB, Atreya SK, Carignan GR, Donahue TM, Haberman JA, Harpold DN, Hartle RE, Hunten DM, Kasprzak WT, Mahaffy PR, Owen TC, Way SH. The composition of the Jovian atmosphere as determined by the Galileo probe mass spectrometer. J Geophys Res 1998; 103:22831-45. [PMID: 11543372 DOI: 10.1029/98je01050] [Citation(s) in RCA: 266] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The Galileo probe mass spectrometer determined the composition of the Jovian atmosphere for species with masses between 2 and 150 amu from 0.5 to 21.1 bars. This paper presents the results of analysis of some of the constituents detected: H2, He, Ne, Ar, Kr, Xe, CH4, NH3, H2O, H2S, C2 and C3 nonmethane hydrocarbons, and possibly PH3 and Cl. 4He/H2 in the Jovian atmosphere was measured to be 0.157 +/- 0.030. 13C/C12 was found to be 0.0108 +/- 0.0005, and D/H and 3He/4He were measured. Ne was depleted, < or = 0.13 times solar, Ar < or = 1.7 solar, Kr < or = 5 solar, and Xe < or = 5 solar. CH4 has a constant mixing ratio of (2.1 +/- 0.4) x 10(-3) (12C, 2.9 solar), where the mixing ratio is relative to H2. Upper limits to the H2O mixing ratio rose from 8 x 10(-7) at pressures <3.8 bars to (5.6 +/- 2.5) x 10(-5) (16O, 0.033 +/- 0.015 solar) at 11.7 bars and, provisionally, about an order of magnitude larger at 18.7 bars. The mixing ratio of H2S was <10(-6) at pressures less than 3.8 bars but rose from about 0.7 x 10(-5) at 8.7 bars to about 7.7 x 10(-5) (32S, 2.5 solar) above 15 bars. Only very large upper limits to the NH3 mixing ratio have been set at present. If PH3 and Cl were present, their mixing ratios also increased with pressure. Species were detected at mass peaks appropriate for C2 and C3 hydrocarbons. It is not yet clear which of these were atmospheric constituents and which were instrumentally generated. These measurements imply (1) fractionation of 4He, (2) a local, altitude-dependent depletion of condensables, probably because the probe entered the descending arm of a circulation cell, (3) that icy planetesimals made significant contributions to the volatile inventory, and (4) a moderate decrease in D/H but no detectable change in (D + 3He)/H in this part of the galaxy during the past 4.6 Gyr.
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Affiliation(s)
- H B Niemann
- Goddard Space Flight Center, Greenbelt, Maryland, USA
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