Isotopes of chlorine from HCl in the Martian atmosphere

Hydrogen chloride gas was recently discovered in the atmosphere of Mars during southern summer seasons. Its connection with potential chlorine reservoirs and related atmospheric chemistry is now particular interest actively studied. Measurements by Atmospheric Chemistry Suite mid-infrared channel (ACS MIR) on ExoMars Trace Gas Orbiter allow us to measure ratio hydrogen two stable isotopologues, H 35 Cl 37 Cl. This work describes observation, processing technique, derived values for isotope ratio. Unlike other volatiles Martian atmosphere, because it enriched heavier isotopes, δ measured be − 7 ± 20°, which almost indistinguishable from terrestrial chlorine. value agrees available measurements surface materials Mars. We conclude that observed HCl likely originates dust not involved any long-term, surface-atmosphere cycle.