Light source for this moon.
Unfortunately the light source is visible unless you turn off glow in atmosphere, but that also kills some of the moons glowing effect.
I am not sure why this happens. The light source is technically far from the moon and planet and shouldn't have any "Focused" light hitting the atmosphere. Seems like a bug. If it has no visible source and is just light it should have a much larger glow cascading onto the atmospheres.