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Sánchez-Lavega A, García-Muñoz A, Del Río-Gaztelurrutia T, Pérez-Hoyos S, Sanz-Requena JF, Hueso R, Guerlet S, Peralta J. Multilayer hazes over Saturn's hexagon from Cassini ISS limb images. Nat Commun 2020; 11:2281. [PMID: 32385300 PMCID: PMC7210256 DOI: 10.1038/s41467-020-16110-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 04/06/2020] [Indexed: 11/09/2022] Open
Abstract
In June 2015, Cassini high-resolution images of Saturn's limb southwards of the planet's hexagonal wave revealed a system of at least six stacked haze layers above the upper cloud deck. Here, we characterize those haze layers and discuss their nature. Vertical thickness of layers ranged from 7 to 18 km, and they extended in altitude ∼130 km, from pressure level 0.5 bar to 0.01 bar. Above them, a thin but extended aerosol layer reached altitude ∼340 km (0.4 mbar). Radiative transfer modeling of spectral reflectivity shows that haze properties are consistent with particles of diameter 0.07-1.4 μm and number density 100-500 cm-3. The nature of the hazes is compatible with their formation by condensation of hydrocarbon ices, including acetylene and benzene at higher altitudes. Their vertical distribution could be due to upward propagating gravity waves generated by dynamical forcing by the hexagon and its associated eastward jet.
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Affiliation(s)
- A Sánchez-Lavega
- Departamento Física Aplicada I, Escuela de Ingeniería de Bilbao, Universidad del País Vasco UPV/EHU, Bilbao, Spain.
| | - A García-Muñoz
- Zentrum für Astronomie und Astrophysik, Technische Universität Berlin, Berlin, Germany
| | - T Del Río-Gaztelurrutia
- Departamento Física Aplicada I, Escuela de Ingeniería de Bilbao, Universidad del País Vasco UPV/EHU, Bilbao, Spain
| | - S Pérez-Hoyos
- Departamento Física Aplicada I, Escuela de Ingeniería de Bilbao, Universidad del País Vasco UPV/EHU, Bilbao, Spain
| | - J F Sanz-Requena
- Departamento de Física Teórica, Atómica y Optica, Universidad de Valladolid, Valladolid, Spain
| | - R Hueso
- Departamento Física Aplicada I, Escuela de Ingeniería de Bilbao, Universidad del País Vasco UPV/EHU, Bilbao, Spain
| | - S Guerlet
- Laboratoire de Meteorologie Dynamique/Institut Pierre-Simon Laplace (LMD/IPSL), Sorbonne Universite, Centre National de la Recherche Scientifique (CNRS), Ecole Polytechnique, Ecole Normale Superieure (ENS), Paris, France
| | - J Peralta
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Kanagawa, Japan
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Andrews DJ, Barabash S, Edberg NJT, Gurnett DA, Hall BES, Holmström M, Lester M, Morgan DD, Opgenoorth HJ, Ramstad R, Sanchez-Cano B, Way M, Witasse O. Plasma observations during the Mars atmospheric "plume" event of March-April 2012. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2016; 121:3139-3154. [PMID: 29552437 PMCID: PMC5854877 DOI: 10.1002/2015ja022023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We present initial analysis and conclusions from plasma observations made during the reported "Mars plume event" of March - April 2012. During this period, multiple independent amateur observers detected a localized, high-altitude "plume" over the Martian dawn terminator [Sanchez-Lavega et al., Nature, 2015, doi:10.1038/nature14162], the cause of which remains to be explained. The estimated brightness of the plume exceeds that expected for auroral emissions, and its projected altitude greatly exceeds that at which clouds are expected to form. We report on in-situ measurements of ionospheric plasma density and solar wind parameters throughout this interval made by Mars Express, obtained over the same surface region, but at the opposing terminator. Measurements in the ionosphere at the corresponding location frequently show a disturbed structure, though this is not atypical for such regions with intense crustal magnetic fields. We tentatively conclude that the formation and/or transport of this plume to the altitudes where it was observed could be due in part to the result of a large interplanetary coronal mass ejection (ICME) encountering the Martian system. Interestingly, we note that the only similar plume detection in May 1997 may also have been associated with a large ICME impact at Mars.
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Affiliation(s)
- D J Andrews
- Swedish Institute of Space Physics (Uppsala), Uppsala, Sweden
| | - S Barabash
- Swedish Institute of Space Physics (Kiruna), Kiruna, Sweden
| | - N J T Edberg
- Swedish Institute of Space Physics (Uppsala), Uppsala, Sweden
| | - D A Gurnett
- Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa, USA
| | - B E S Hall
- Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
| | - M Holmström
- Swedish Institute of Space Physics (Kiruna), Kiruna, Sweden
| | - M Lester
- Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
| | - D D Morgan
- Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa, USA
| | - H J Opgenoorth
- Swedish Institute of Space Physics (Uppsala), Uppsala, Sweden
| | - R Ramstad
- Swedish Institute of Space Physics (Kiruna), Kiruna, Sweden
| | - B Sanchez-Cano
- Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
| | - M Way
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, New York, USA
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20, Uppsala, Sweden
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Andersson L, Weber TD, Malaspina D, Crary F, Ergun RE, Delory GT, Fowler CM, Morooka MW, McEnulty T, Eriksson AI, Andrews DJ, Horanyi M, Collette A, Yelle R, Jakosky BM. Dust observations at orbital altitudes surrounding Mars. Science 2015; 350:aad0398. [PMID: 26542578 DOI: 10.1126/science.aad0398] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Dust is common close to the martian surface, but no known process can lift appreciable concentrations of particles to altitudes above ~150 kilometers. We present observations of dust at altitudes ranging from 150 to above 1000 kilometers by the Langmuir Probe and Wave instrument on the Mars Atmosphere and Volatile Evolution spacecraft. Based on its distribution, we interpret this dust to be interplanetary in origin. A comparison with laboratory measurements indicates that the dust grain size ranges from 1 to 12 micrometers, assuming a typical grain velocity of ~18 kilometers per second. These direct observations of dust entering the martian atmosphere improve our understanding of the sources, sinks, and transport of interplanetary dust throughout the inner solar system and the associated impacts on Mars's atmosphere.
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Affiliation(s)
- L Andersson
- Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA.
| | - T D Weber
- Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA
| | - D Malaspina
- Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA
| | - F Crary
- Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA
| | - R E Ergun
- Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA
| | - G T Delory
- Space Science Laboratory, University of California-Berkeley, Berkeley, CA 94720, USA
| | - C M Fowler
- Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA
| | - M W Morooka
- Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA
| | - T McEnulty
- Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA
| | - A I Eriksson
- Swedish Institute of Space Physics, Uppsala, Sweden
| | - D J Andrews
- Swedish Institute of Space Physics, Uppsala, Sweden
| | - M Horanyi
- Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA
| | - A Collette
- Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA
| | - R Yelle
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA
| | - B M Jakosky
- Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA
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