Its 40,000 years going round, 99% of the time it can't be seen. Maybe they only know how close it gets to the sun and how far it gets but the actual shape of the orbit might depend on the material the body is made of and how it interacts with other objects such as Planet X, none of which is known. Maybe the numbers they are releasing are just approximations that can't give exact information like the radius. Maybe a 40,000 year orbit experiences changes to its dimension, gets squeezed or lengthened depending on what it comes close as it orbits the sun. Could even be a little different every time it goes around.Gah! I wish they'd actually mentioned its orbital radius!