Airglow

A unique visual phenomenon caused by trace atmospheric compounds and cosmic ray interactions, the Vieneo airglow paints the night sky with a faint, ethereal blue-green glow. Most noticeable at night in high-altitude regions, this effect highlights the alien beauty of the exomoon's upper atmosphere.

Overview

The airglow effect on Vieneo is a chemiluminescent emission caused by high-altitude interactions between cosmic rays and trace amounts of methane (CH₄) and ammonia (NH₃) in the atmosphere. These energetic interactions excite the molecules, which then emit photons in the visible spectrum, most notably in the blue-green region.

Unlike auroras, which are guided by magnetic field lines and solar wind interactions, this airglow is more diffuse and continuous, occurring even on the planet's nightside when the sun is fully occluded. The effect is strongest in the upper atmosphere, where cosmic ray penetration is sufficient and the remaining density of reactive molecules is still meaningful.