Transient HCl in the atmosphere of Mars

Korablev, Oleg; Olsen, Kevin S.; Trokhimovskiy, Alexander; Lefèvre, Franck; Montmessin, Franck; Fedorova, Anna A.; Toplis, Michael J.; Alday, Juan; Belyaev, Denis A.; Patrakeev, Andrey; Ignatiev, Nikolay I.; Shakun, Alexey V.; Grigoriev, Alexey V.; Baggio, Lucio; Abdenour, Irbah; Lacombe, Gaetan; Ivanov, Yury S.; Aoki, Shohei; Thomas, Ian R.; Daerden, Frank; Ristic, Bojan; Erwin, Justin T.; Patel, Manish; Bellucci, Giancarlo; Lopez-Moreno, Jose-Juan and Vandaele, Ann C. (2021). Transient HCl in the atmosphere of Mars. Science Advances, 7(7), article no. eabe4386.



A major quest in Mars’ exploration has been the hunt for atmospheric gases, potentially unveiling ongoing activity of geophysical or biological origin. Here, we report the first detection of a halogen gas, HCl, which could, in theory, originate from contemporary volcanic degassing or chlorine released from gas-solid reactions. Our detections made at ~3.2 to 3.8 μm with the Atmospheric Chemistry Suite and confirmed with Nadir and Occultation for Mars Discovery instruments onboard the ExoMars Trace Gas Orbiter, reveal widely distributed HCl in the 1- to 4-ppbv range, 20 times greater than previously reported upper limits. HCl increased during the 2018 global dust storm and declined soon after its end, pointing to the exchange between the dust and the atmosphere. Understanding the origin and variability of HCl shall constitute a major advance in our appraisal of martian geo- and photochemistry.

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  • Item ORO ID
  • 75328
  • Item Type
  • Journal Item
  • ISSN
  • 2375-2548
  • Academic Unit or School
  • Faculty of Science, Technology, Engineering and Mathematics (STEM) > Physical Sciences
    Faculty of Science, Technology, Engineering and Mathematics (STEM)
  • Copyright Holders
  • © 2021 Oleg Korablev, © 2021 Kevin S. Olsen, © 2021 Alexander Trokhimovskiy, © 2021 Franck Lefèvre, © 2021 Franck Montmessin, © 2021 Anna A. Fedorova, © 2021 Michael J. Toplis, © 2021 Juan Alday, © 2021 Denis A. Belyaev, © 2021 Andrey Patrakeev, © 2021 Nikolay I. Ignatiev, © 2021 Alexey V. Shakun, © 2021 Alexey V. Grigoriev, © 2021 Lucio Baggio, © 2021 Irbah Abdenour, © 2021 Gaetan Lacombe, © 2021 Yury S. Ivanov, © 2021 Shohei Aoki, © 2021 Ian R. Thomas, © 2021 Frank Daerdan, © 2021 Bojan Ristic, © 2021 Justin T. Erwin, © 2021 Manish Patel, © 2021 Giancarlo Bellucci, © 2021 Jose-Juan Lopez-Moreno, © 2021 Ann C. Vandaele
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