The amount of water suggests that the planet actually developed far away from the star, where it was bombarded by a lot of icy material. (wasp-planets.net)
The mysterious bright spot on the dwarf planet Ceres has been revealed in its highest resolution yet, and the bright materials in it appear to be coming from a fractured dome — a possible portal to icy materials in the subsurface. (sciencemag.org)
Perhaps icy material from the rings fell onto them, piling up near the equator to form the ridges. (newscientist.com)