Yeah, more Sci-Fi..

Good colors and scene, i love the crispness of the surface!
Bright as it shines, you could set up a second, non visible sun, with lower power to the surface (Light/Glow atmosphere off), right at the place where the lightsource of the ring structure is for additional visual soft light/shadows maybe.
You could also try to set your main sun/lightsource to non visible and putting it right into the place of the ring structures lightsource just for fun (a very weak fill light for surfaces only opposite direction to the sun might be needed)..