Strong water isotopic anomalies in the martian atmosphere: Probing current and ancient reservoirs
| Autor: | A. S. J. Khayat, M. D. Smith, Robert E. Novak, Michael J. Mumma, Paul Hartogh, H. U. Kaufl, Geronimo L. Villanueva, Alan T. Tokunaga, Th. Encrenaz |
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| Přispěvatelé: | NASA Goddard Space Flight Center (GSFC), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Observatoire de Paris, Université Paris sciences et lettres (PSL), Institute for Astronomy [Honolulu], University of Hawai'i [Honolulu] (UH) |
| Rok vydání: | 2015 |
| Předmět: |
Extraterrestrial Environment
010504 meteorology & atmospheric sciences Mars Atmospheric sciences 01 natural sciences Atmosphere chemistry.chemical_compound 0103 physical sciences Deuterium Oxide 010303 astronomy & astrophysics ComputingMilieux_MISCELLANEOUS 0105 earth and related environmental sciences Orographic lift [PHYS]Physics [physics] Heavy water Martian Vienna Standard Mean Ocean Water Multidisciplinary Ice Water Mars Exploration Program Atmosphere of Mars Deuterium chemistry 13. Climate action [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] Evolution Planetary Geology |
| Zdroj: | Science Science, American Association for the Advancement of Science, 2015, 348 (6231), pp.218-221. ⟨10.1126/science.aaa3630⟩ |
| ISSN: | 1095-9203 0036-8075 |
| DOI: | 10.1126/science.aaa3630 |
| Popis: | Mapping Mars' water history We know the water cycle on Earth is complex. Neither is it simple on Mars. Infrared maps of water isotopes made by Villanueva et al. show the distribution of H2O and "semiheavy" water (HDO: deuterated water containing a mixture of hydrogen isotopes) across Mars. HDO enrichment varies with time and location; for example, irregular isotopic signals associate with different terrain features. The measurements also allow seasonal sublimation levels of the northern ice cap to be estimated and thus could be used to reveal past climate behavior. Science, this issue p. 218 We measured maps of atmospheric water (H2O) and its deuterated form (HDO) across the martian globe, showing strong isotopic anomalies and a significant high deuterium/hydrogen (D/H) enrichment indicative of great water loss. The maps sample the evolution of sublimation from the north polar cap, revealing that the released water has a representative D/H value enriched by a factor of about 7 relative to Earth's ocean [Vienna standard mean ocean water (VSMOW)]. Certain basins and orographic depressions show even higher enrichment, whereas high-altitude regions show much lower values (1 to 3 VSMOW). Our atmospheric maps indicate that water ice in the polar reservoirs is enriched in deuterium to at least 8 VSMOW, which would mean that early Mars (4.5 billion years ago) had a global equivalent water layer at least 137 meters deep. Maps of atmospheric water distribution reveal seasonal and spatial variations in the enrichment of deuterium to hydrogen. Maps of atmospheric water distribution reveal seasonal and spatial variations in the enrichment of deuterium to hydrogen. |
| Databáze: | OpenAIRE |
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