Emirates Mars Ultraviolet Spectrometers Observation of Argon I 104.8 nm and 106.6 nm in the Martian Thermosphere.

The Emirates Mars Ultraviolet Spectrometer (EMUS) is one of the three instruments on-board the Emirates Mars Mission (EMM) Hope probe that arrived at Mars on February 9, 2021. EMUS is a far ultraviolet spectrometer designed to observe the spatial and temporal variability of key constituents in the Martian thermosphere (100-200 km altitude) and exosphere (>200 km altitude). EMUS has observed the two neutral argon emission lines Ar I 104.8 nm and Ar I 106.6 nm and produced the first disk resolved images of Ar I 106.6 nm. This work will showcase how the brightness of the argon emission lines vary with different factors such as emission angle (EA) and solar zenith angle (SZA). We will compare the measurements obtained from EMUS with forward-modeling simulations of argons electron impact and solar resonant fluorescent sources.