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Grava C, Killen RM, Benna M, Berezhnoy AA, Halekas JS, Leblanc F, Nishino MN, Plainaki C, Raines JM, Sarantos M, Teolis BD, Tucker OJ, Vervack RJ, Vorburger A. Volatiles and Refractories in Surface-Bounded Exospheres in the Inner Solar System. SPACE SCIENCE REVIEWS 2021; 217:61. [PMID: 34720217 PMCID: PMC8550778 DOI: 10.1007/s11214-021-00833-8] [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: 12/22/2020] [Accepted: 05/21/2021] [Indexed: 06/13/2023]
Abstract
Volatiles and refractories represent the two end-members in the volatility range of species in any surface-bounded exosphere. Volatiles include elements that do not interact strongly with the surface, such as neon (detected on the Moon) and helium (detected both on the Moon and at Mercury), but also argon, a noble gas (detected on the Moon) that surprisingly adsorbs at the cold lunar nighttime surface. Refractories include species such as calcium, magnesium, iron, and aluminum, all of which have very strong bonds with the lunar surface and thus need energetic processes to be ejected into the exosphere. Here we focus on the properties of species that have been detected in the exospheres of inner Solar System bodies, specifically the Moon and Mercury, and how they provide important information to understand source and loss processes of these exospheres, as well as their dependence on variations in external drivers.
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Affiliation(s)
- Cesare Grava
- Southwest Research Institute, San Antonio, TX USA
| | | | - Mehdi Benna
- NASA Goddard Space Flight Center, Greenbelt, MD USA
- University of Maryland Baltimore County, Baltimore, MD USA
| | - Alexey A Berezhnoy
- Sternberg Astronomical Institute, Moscow State University, Moscow, Russia
- Institute of Physics, Kazan Federal University, Kazan, Russia
| | - Jasper S Halekas
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA USA
| | | | - Masaki N Nishino
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa Japan
| | | | - Jim M Raines
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI USA
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Livengood T, Chin G, Sagdeev R, Mitrofanov I, Boynton W, Evans L, Litvak M, McClanahan T, Sanin A, Starr R, Su J. Moonshine: Diurnally varying hydration through natural distillation on the Moon, detected by the Lunar Exploration Neutron Detector (LEND). ICARUS 2015; 255:100-115. [PMID: 28798496 PMCID: PMC5548521 DOI: 10.1016/j.icarus.2015.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The Lunar Exploration Neutron Detector (LEND), on the polar-orbiting Lunar Reconnaissance Orbiter (LRO) spacecraft, has detected suppression in the Moon's naturally-occurring epithermal neutron leakage flux that is consistent with the presence of diurnally varying quantities of hydrogen in the regolith near the equator. Peak hydrogen concentration (neutron flux suppression) is on the dayside of the dawn terminator and diminishes through the dawn-to-noon sector. The minimum concentration of hydrogen is in the late afternoon and dusk sector. The chemical form of hydrogen is not determinable from these measurements, but other remote sensing methods and anticipated elemental availability suggest water molecules or hydroxyl ions. Signal-to-noise ratio at maximum contrast is 5.6σ in each of two detector systems. Volatiles are deduced to collect in or on the cold nightside surface and distill out of the regolith after dawn as rotation exposes the surface to sunlight. Liberated volatiles migrate away from the warm subsolar region toward the nearby cold nightside surface beyond the terminator, resulting in maximum concentration at the dawn terminator. The peak concentration within the upper ~1 m of regolith is estimated to be 0.0125 ± 0.0022 weight-percent water-equivalent hydrogen (wt% WEH) at dawn, yielding an accumulation of 190 ± 30 ml recoverable water per square meter of regolith at each dawn. Volatile transport over the lunar surface in opposition to the Moon's rotation exposes molecules to solar ultraviolet radiation. The short lifetime against photolysis and permanent loss of hydrogen from the Moon requires a resupply rate that greatly exceeds anticipated delivery of hydrogen by solar wind implantation or by meteoroid impacts, suggesting that the surface inventory must be continually resupplied by release from a deep volatile inventory in the Moon. The natural distillation of water from the regolith by sunlight and its capture on the cold night surface may provide energy-efficient access to volatiles for in situ resource utilization (ISRU) by direct capture before volatiles can enter the surface, eliminating the need to actively mine regolith for volatile resource recovery.
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Affiliation(s)
- T.A. Livengood
- CRESST/University of Maryland at Planetary Systems Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771, United States
| | - G. Chin
- Planetary Systems Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771, United States
| | - R.Z. Sagdeev
- Department of Physics, University of Maryland, College Park, MD 20742, United States
| | | | - W.V. Boynton
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, United States
| | - L.G. Evans
- Computer Sciences Corporation, Lanham-Seabrook, MD 20706, United States
| | - M.L. Litvak
- Institute for Space Research, Moscow, Russia
| | - T.P. McClanahan
- Astrochemistry Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771, United States
| | - A.B. Sanin
- Institute for Space Research, Moscow, Russia
| | - R.D. Starr
- Department of Physics, Catholic University of America, Washington, DC 20064, United States
| | - J.J. Su
- Department of Physics, University of Maryland, College Park, MD 20742, United States
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Paige DA, Siegler MA, Harmon JK, Neumann GA, Mazarico EM, Smith DE, Zuber MT, Harju E, Delitsky ML, Solomon SC. Thermal stability of volatiles in the north polar region of Mercury. Science 2012. [PMID: 23196905 DOI: 10.1126/science.1231106] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Thermal models for the north polar region of Mercury, calculated from topographic measurements made by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, show that the spatial distribution of regions of high radar backscatter is well matched by the predicted distribution of thermally stable water ice. MESSENGER measurements of near-infrared surface reflectance indicate bright surfaces in the coldest areas where water ice is predicted to be stable at the surface, and dark surfaces within and surrounding warmer areas where water ice is predicted to be stable only in the near subsurface. We propose that the dark surface layer is a sublimation lag deposit that may be rich in impact-derived organic material.
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Affiliation(s)
- David A Paige
- Department of Earth and Space Sciences, University of California, Los Angeles, CA 90095, USA.
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Gladstone GR, Retherford KD, Egan AF, Kaufmann DE, Miles PF, Parker JW, Horvath D, Rojas PM, Versteeg MH, Davis MW, Greathouse TK, Slater DC, Mukherjee J, Steffl AJ, Feldman PD, Hurley DM, Pryor WR, Hendrix AR, Mazarico E, Stern SA. Far-ultraviolet reflectance properties of the Moon's permanently shadowed regions. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011je003913] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Neish CD, Bussey DBJ, Spudis P, Marshall W, Thomson BJ, Patterson GW, Carter LM. The nature of lunar volatiles as revealed by Mini-RF observations of the LCROSS impact site. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010je003647] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Paige DA, Siegler MA, Zhang JA, Hayne PO, Foote EJ, Bennett KA, Vasavada AR, Greenhagen BT, Schofield JT, McCleese DJ, Foote MC, DeJong E, Bills BG, Hartford W, Murray BC, Allen CC, Snook K, Soderblom LA, Calcutt S, Taylor FW, Bowles NE, Bandfield JL, Elphic R, Ghent R, Glotch TD, Wyatt MB, Lucey PG. Diviner Lunar Radiometer Observations of Cold Traps in the Moon's South Polar Region. Science 2010; 330:479-82. [DOI: 10.1126/science.1187726] [Citation(s) in RCA: 294] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Duke MB. Lunar polar ice deposits: scientific and utilization objectives of the Lunar Ice Discovery Mission proposal. ACTA ASTRONAUTICA 2002; 50:379-383. [PMID: 11902177 DOI: 10.1016/s0094-5765(01)00184-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The Clementine mission has revived interest in the possibility that ice exists in shadowed craters near the lunar poles. Theoretically, the problem is complex, with several possible sources of water (meteoroid, asteroid, comet impact), several possible loss mechanisms (impact vaporization, sputtering, photoionization), and burial by meteorite impact. Opinions of modelers have ranged from no ice to several times 10(16) g of ice in the cold traps. Clementine bistatic radar data have been interpreted in favor of the presence of ice, while Arecibo radar data do not confirm its presence. The Lunar Prospector mission, planned to be flown in the fall of 1997, could gather new evidence for the existence of ice. If ice is present, both scientific and utilitarian objectives would be addressed by a lunar polar rover, such as that proposed to the NASA Discovery program, but not selected. The lunar polar rover remains the best way to understand the distribution and characteristics of lunar polar ice.
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Affiliation(s)
- Michael B Duke
- Lunar and Planetary Institute, Houston, Texas 77058, USA
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Nozette S, Spudis PD, Robinson MS, Bussey DBJ, Lichtenberg C, Bonner R. Integration of lunar polar remote-sensing data sets: Evidence for ice at the lunar south pole. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000je001417] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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11
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Crider DH, Vondrak RR. The solar wind as a possible source of lunar polar hydrogen deposits. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/2000je001277] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Potter AE, Killen RM, Morgan TH. Variation of lunar sodium during passage of the Moon through the Earth's magnetotail. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/1999je001213] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Feldman WC, Lawrence DJ, Elphic RC, Barraclough BL, Maurice S, Genetay I, Binder AB. Polar hydrogen deposits on the Moon. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/1999je001129] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Yakshinskiy BV, Madey TE. Photon-stimulated desorption as a substantial source of sodium in the lunar atmosphere. Nature 1999; 400:642-4. [PMID: 10458159 DOI: 10.1038/23204] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mercury and the Moon both have tenuous atmospheres that contain atomic sodium and potassium. These chemicals must be continuously resupplied, as neither body can retain the atoms for more than a few hours. The mechanisms proposed to explain the resupply include sputtering of the surface by the solar wind, micrometeorite impacts, thermal desorption and photon-stimulated desorption. But there are few data and no general agreement about which processes dominate. Here we report laboratory studies of photon-stimulated desorption of sodium from surfaces that simulate lunar silicates. We find that bombardment of such surfaces at temperatures of approximately 250 K by ultraviolet photons (wavelength lambda < 300 nm) causes very efficient desorption of sodium atoms, induced by electronic excitations rather than by thermal processes or momentum transfer. The flux at the lunar surface of ultraviolet photons from the Sun is sufficient to ensure that photon-stimulated desorption of sodium contributes substantially to the Moon's atmosphere. On Mercury, solar heating of the surface implies that thermal desorption will also be an important source of atmospheric sodium.
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Affiliation(s)
- B V Yakshinskiy
- Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway 08854-8019, USA
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Margot JL, Campbell DB, Jurgens RF, Slade MA. Topography of the lunar poles from radar interferometry: a survey of cold trap locations. Science 1999; 284:1658-60. [PMID: 10356393 DOI: 10.1126/science.284.5420.1658] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Detailed topographic maps of the lunar poles have been obtained by Earth-based radar interferometry with the 3.5-centimeter wavelength Goldstone Solar System Radar. The interferometer provided maps 300 kilometers by 1000 kilometers of both polar regions at 150-meter spatial resolution and 50-meter height resolution. Using ray tracing, these digital elevation models were used to locate regions that are in permanent shadow from solar illumination and may harbor ice deposits. Estimates of the total extent of shadowed areas poleward of 87.5 degrees latitude are 1030 and 2550 square kilometers for the north and south poles, respectively.
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Affiliation(s)
- J L Margot
- Department of Astronomy, Space Sciences Building, Cornell University, Ithaca, NY 14853, USA
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Feldman WC, Maurice S, Binder AB, Barraclough BL, Elphic RC, Lawrence DJ. Fluxes of fast and epithermal neutrons from Lunar Prospector: evidence for water ice at the lunar poles. Science 1998; 281:1496-500. [PMID: 9727973 DOI: 10.1126/science.281.5382.1496] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Maps of epithermal- and fast-neutron fluxes measured by Lunar Prospector were used to search for deposits enriched in hydrogen at both lunar poles. Depressions in epithermal fluxes were observed close to permanently shaded areas at both poles. The peak depression at the North Pole is 4.6 percent below the average epithermal flux intensity at lower latitudes, and that at the South Pole is 3.0 percent below the low-latitude average. No measurable depression in fast neutrons is seen at either pole. These data are consistent with deposits of hydrogen in the form of water ice that are covered by as much as 40 centimeters of desiccated regolith within permanently shaded craters near both poles.
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Affiliation(s)
- W C Feldman
- Los Alamos National Laboratory, MS D-466, Los Alamos, NM 87545, USA.
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17
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Potter AE, Morgan TH. Coronagraphic observations of the lunar sodium exosphere near the lunar surface. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98je00059] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Madey TE, Yakshinskiy BV, Ageev VN, Johnson RE. Desorption of alkali atoms and ions from oxide surfaces: Relevance to origins of Na and K in atmospheres of Mercury and the Moon. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98je00230] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Search for lunar pickup ions. ACTA ACUST UNITED AC 1998. [DOI: 10.1016/s0964-2749(98)80011-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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20
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Butler BJ. The migration of volatiles on the surfaces of Mercury and the Moon. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97je01347] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Mendillo M, Baumgardner J. Constraints on the origin of the Moon's atmosphere from observations during a lunar eclipse. Nature 1995; 377:404-6. [PMID: 7566115 DOI: 10.1038/377404a0] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The properties of the Moon's rarefied atmosphere, which can be traced through observations of sodium and potassium, provide important insights into the formation and maintenance of atmospheres on other primitive Solar System bodies. The lunar atmosphere is believed to be composed of atoms from the surface rocks and soil, which might have been sputtered by micrometeorites, by ions in the solar wind, or by photons. It might also form by the evaporation of atoms from the hot, illuminated surface. Here we report the detection of sodium emission from the Moon's atmosphere during a total lunar eclipse (which occurs when the Moon is full). The sodium atmosphere is considerably more extended at full Moon than expected--it extends to at least nine lunar radii--and its brightness distribution is incompatible with sources involving either solar-wind or micrometeorite sputtering. This leaves photon sputtering or thermal desorption as the preferred explanations for the lunar atmosphere, and suggests that sunlight might also be responsible for the transient atmospheres of other primitive bodies (such as Mercury).
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Affiliation(s)
- M Mendillo
- Center for Space Physics, Boston University, Massachusetts 02215, USA
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Abstract
Atomic sodium is a useful tracer of the tenuous lunar atmosphere because of its high efficiency in scattering sunlight at the D(1) (5896 angstroms) and D(2) (5890 angstroms) wavelengths. In 1988, Earth-based instruments revealed the presence of sodium at a density of less than 50 atoms per cubic centimeter at lunar altitudes below 100 kilometers. Telescopic observations that are made with a coronograph technique to block out the disk of the moon allow a true picture of the circumiunar atmosphere to be obtained and show the presence of sodium out to a distance of several lunar radii. The distribution of sodium has a solar zenith angle dependence, suggesting that most of the sodium that reaches great altitudes is liberated from the moon's surface by solar photons (by heating or sputtering) or by solar wind impact, in contrast to a source driven by uniform micrometeor bombardment.
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Killen RM, Morgan TH. Diffusion of Na and K in the uppermost regolith of Mercury. ACTA ACUST UNITED AC 1993. [DOI: 10.1029/93je02617] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Butler BJ, Muhleman DO, Slade MA. Mercury: full-disk radar images and the detection and stability of ice at the North Pole. ACTA ACUST UNITED AC 1993. [DOI: 10.1029/93je01581] [Citation(s) in RCA: 155] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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