 For comparison, Pluto, the largest object in the Kuiper belt, is about in diameter.Astronomer Michael Brown assumes an albedo of 0.11 and calculates a diameter of 626 km, while the Johnston's Archive gives a diameter of 770 kilometers, based on an assumed albedo of 0.09.All of these estimates assume that is a single object, the discovery of a large satellite means that the size is likely to be smaller.