Thank you AP for putting efforts into this, I'll study your file soon. I did a bit more research regarding the composition of airglow, here is the basic components, feel free to take a look.
One thing I got from this image is that we need basically 3 layers of airglow, first is green, then yellow and orange, and none of them have sharp edges, just naturally fading away.
Another question is, where the green tint comes from, I didn't find any green color setting in the nodes?