This is SO awesome. I'm very interested in learning this kind of code. You're using Godot's shader language based on GLSL, yes? Do you have any suggestions for resources and/or projects to start learning that?
Also, any plans for including other kinds of stellar objects with slightly different shapes? Stuff like black holes with smaller or different accretion disks, or different planets and/or gas giants with different rings, or even stuff like neutron stars or white dwarfs with polar jets? I'd offer my full support to develop those, but I'm clueless in shaders.