Located deep below the Galactic plane, the system of Greae Phio CB-X d1-600 is a binary system comprised of an A-type subdwarf and an F-type main sequence star. The system got its nickname "Ruby in the Sky", however, for the ringed Y-type brown dwarf (B 6) at its very fringes.

Specifically, the Ruby has an expansive ring system and, more importantly, a ringed ice moon (B 6 c) with an orbital inclination of -89 degrees. Due to its colouration the moon is dubbed the "Marble".

The Marble itself has a thin oxygen atmosphere, and a convenient surface gravity of 0.3 g. Hence, it can be safely landed on. Due to the moon’s high inclination, explorers of its glittering, frozen surface can take in the magnificent top view sights of the Marble’s rings "crossing" those of the Ruby. As the Marble is tidally-locked, those sights are persistent.

Sadly, the Marble has no volcanic activity or signs of life. Quite possibly, the location is just too remote. The surface is mostly even with the occasional mountain range dotting the planet. What is striking, however, are the vast "ice dune" features that are spread all across the surface.

It has been theorised that these dunes may be the result of either the Y-dwarf's own meagre radiation (i.e. solar wind) or that of the binary F-type star. In any case, due to the thin oxygen atmosphere and the abundance of water ice it's possible that the stream of radiation is sufficient to energize ice molecules and makes them move across the surface. This theory is yet to be proven, however.

Additional information:
The system has another landable moon (B 3) which as of November 14th 3308 has not been mapped nor surveyed.