Simplified Relations for the Martian Night-Time OH* Suitable for the Interpretation of Observations

Abstract

Observations of excited hydroxyl (OH*) emissions are broadly used for inferring information about atmospheric dynamics and composition. We present several analytical approximations for characterizing the excited hydroxyl layer in the Martian atmosphere. They include the OH* number density at the maximum and the height of the peak, along with the relations for assessing different impacts on the OH* layer under night-time conditions. These characteristics are determined by the ambient temperature, atomic oxygen concentration, and their vertical gradients. The derived relations can be used for the analysis of airglow measurements and the interpretation of their variations.

Keywords

• Mars
• excited hydroxyl
• Martian atmosphere
• airglow
• OH*
• nightglow