airglow

EuroPlanet Science Congress - Berlin

Explore the fascinating insights from Hadrien's thesis here.

Airglow

©ESA; Photo: Airglow observed from the International Space Station


 

In the summer of 2024, our consultant Hadrien Robin joined VeroTech as a Satellite Test Engineer. As a graduate of the University of Liège with a Master’s in Space Sciences, Hadrien's thesis achieved remarkable results, earning him the opportunity for his work to be presented at the EuroPlanet Science Congress in Berlin! 

In Hadrien’s thesis “Time Variations of the Martian Dayglow”, he analysed the temporal variation of the Martian airglow and demonstrated a strong correlation between the intensity of the Lyman-alpha emissions, produced by the hydrogen in the Sun, and the Martian airglow. The amount of Lyman-alpha photon reaching Mars depends mainly on two factors: the distance between the Sun and Mars, and the solar cycle. The altitude at which the airglow occurs is on the other hand only related to the orbital radius. This surprising discovery hints at a complex dynamic system in the Martian atmosphere through the season cycle.

What is an airglow? 

An airglow is a phenomenon that happens when the light from the Sun is absorbed by an atmosphere. The excited molecules of the air will release this energy by producing photons. This is very similar to what happens during an aurora, where molecules release light after the impact of a solar particle. Airglow has been observed on Earth, Mars and many other objects of the solar system. On Earth and Mars, it is mostly green due to the emission of the atomic oxygen.

By observing the atmosphere from orbit using a spectrometer, such as the one on-board of the ExoMars Trace Gas Orbiter mission, it is possible to determine the spectral composition of the airglow. As every molecule emits light at specific wavelengths, one can identify which molecules are responsible for the airglow we observe. This offers a unique opportunity to remotely study the upper atmosphere of Mars. The analysis of the intensity of these emissions and their variations through space and time may serve as proxy for the measurement of other quantities. It can also be used to deepen our understanding of the Martian atmosphere and the interactions existing between numerous atmospheric phenomena.