When dust particles enter the Mars’ atmosphere, collisions with air molecules cause heating and evaporation, and the continuous injection of metal atoms and ions into Mars’ atmosphere.
The MAVEN Imaging Ultraviolet Spectrograph, or IUVS, instrument has detected a layer of Mg+ ions around 95km.
A newly published study explores the unusual chemistry of metallic ions in a CO₂ atmosphere, and then develops a model of magnesium chemistry to explain the observed layer of Mg+ and the surprising absence of a detectable Mg layer.
The model predicts that metals like Mg & Fe form carbonates that condense water to form “dirty” ice particles at the low temperatures in Mars’ upper atmosphere. These particles provide the seeds on which CO₂ can condense at temperatures below 180ºC, thus producing Martian clouds of CO₂-ice particles that have previously been observed from the Martian surface and from orbiters.
Read the full paper in the Journal of Geophysical Research—Planets.