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Cassidy TA, McClintock WE, Killen RM, Sarantos M, Merkel AW, Vervack RJ, Burger MH. A Cold-Pole Enhancement in Mercury's Sodium Exosphere. GEOPHYSICAL RESEARCH LETTERS 2016; 43:12111-11128. [PMID: 29720774 PMCID: PMC5927387 DOI: 10.1002/2016gl071071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The Ultraviolet and Visible Spectrometer (UVVS) component of the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) on the MESSENGER spacecraft characterized the local-time distribution of the sodium exosphere over the course of its orbital mission. The observations show that the sodium exosphere is enhanced above Mercury's cold-pole longitudes. Based on previously published sodium exosphere models we infer that these regions act as nightside surface reservoirs, temporary sinks to the exosphere that collect sodium atoms transported anti-sunward. The reservoirs are revealed as exospheric enhancements when they are exposed to sunlight. As in the models the reservoir is depleted as the cold poles rotate from dawn to dusk, but unlike the models the depletion is only partial. The persistence of the reservoir means that it could, over the course of geologically long periods of time, contribute to an increase in the bulk concentration of sodium near the cold-pole longitudes.
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Affiliation(s)
- Timothy A Cassidy
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA
| | - William E McClintock
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA
| | - Rosemary M Killen
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - Menelaos Sarantos
- Goddard Planetary Heliophysics Institute, University of Maryland Baltimore County, Baltimore, MD 21250, USA
- Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - Aimee W Merkel
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA
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Zurbuchen TH, Raines JM, Gloeckler G, Krimigis SM, Slavin JA, Koehn PL, Killen RM, Sprague AL, McNutt RL, Solomon SC. MESSENGER Observations of the Composition of Mercury's Ionized Exosphere and Plasma Environment. Science 2008; 321:90-2. [DOI: 10.1126/science.1159314] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Thomas H. Zurbuchen
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109–2143, USA
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Academy of Athens, Research Center for Astronomy and Applied Mathematics, Soranou Efessiou 4, Athens 11527, Greece
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- Department of Physics and Astronomy, Eastern Michigan University, 303 Strong Hall, Ypsilanti, MI 48197, USA
| | - Jim M. Raines
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109–2143, USA
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Academy of Athens, Research Center for Astronomy and Applied Mathematics, Soranou Efessiou 4, Athens 11527, Greece
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- Department of Physics and Astronomy, Eastern Michigan University, 303 Strong Hall, Ypsilanti, MI 48197, USA
| | - George Gloeckler
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109–2143, USA
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Academy of Athens, Research Center for Astronomy and Applied Mathematics, Soranou Efessiou 4, Athens 11527, Greece
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- Department of Physics and Astronomy, Eastern Michigan University, 303 Strong Hall, Ypsilanti, MI 48197, USA
| | - Stamatios M. Krimigis
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109–2143, USA
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Academy of Athens, Research Center for Astronomy and Applied Mathematics, Soranou Efessiou 4, Athens 11527, Greece
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- Department of Physics and Astronomy, Eastern Michigan University, 303 Strong Hall, Ypsilanti, MI 48197, USA
| | - James A. Slavin
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109–2143, USA
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Academy of Athens, Research Center for Astronomy and Applied Mathematics, Soranou Efessiou 4, Athens 11527, Greece
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- Department of Physics and Astronomy, Eastern Michigan University, 303 Strong Hall, Ypsilanti, MI 48197, USA
| | - Patrick L. Koehn
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109–2143, USA
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Academy of Athens, Research Center for Astronomy and Applied Mathematics, Soranou Efessiou 4, Athens 11527, Greece
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- Department of Physics and Astronomy, Eastern Michigan University, 303 Strong Hall, Ypsilanti, MI 48197, USA
| | - Rosemary M. Killen
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109–2143, USA
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Academy of Athens, Research Center for Astronomy and Applied Mathematics, Soranou Efessiou 4, Athens 11527, Greece
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- Department of Physics and Astronomy, Eastern Michigan University, 303 Strong Hall, Ypsilanti, MI 48197, USA
| | - Ann L. Sprague
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109–2143, USA
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Academy of Athens, Research Center for Astronomy and Applied Mathematics, Soranou Efessiou 4, Athens 11527, Greece
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- Department of Physics and Astronomy, Eastern Michigan University, 303 Strong Hall, Ypsilanti, MI 48197, USA
| | - Ralph L. McNutt
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109–2143, USA
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Academy of Athens, Research Center for Astronomy and Applied Mathematics, Soranou Efessiou 4, Athens 11527, Greece
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- Department of Physics and Astronomy, Eastern Michigan University, 303 Strong Hall, Ypsilanti, MI 48197, USA
| | - Sean C. Solomon
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109–2143, USA
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Academy of Athens, Research Center for Astronomy and Applied Mathematics, Soranou Efessiou 4, Athens 11527, Greece
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- Department of Physics and Astronomy, Eastern Michigan University, 303 Strong Hall, Ypsilanti, MI 48197, USA
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