planet classObservedMeasured or catalogued in the real sky, with its source cited.ModelPublished physics or a published model, applied as written.
Ice giant
A giant planet made mostly of water, methane and ammonia rather than hydrogen and helium, like Uranus and Neptune. Their interiors are hot, dense fluids, their magnetic fields are lopsided, and planets of about their mass may be among the commonest in the Galaxy.