Javvin is the only moon of Shraak Un, and is fairly small, being 60 km in radius. Its surface is covered in entrances to underground habitation areas, including several large "gravity wheel"-type structures. The surface is relatively smooth and featureless, save for a large impact crater several kilometers in diameter covering a large portion of the surface.

There is also a large and very reflective area composed of silicon, under close examination resembling a factory built on the atomic scale (and hence being invisibly small to the naked eye). The builders and purpose of this area are unknown.