- New giant KBO satellites

The KBOs are 2003 AZ84, Quaoar, 2002 UX25 and Orcus.

Hmm. Really beginning to look as if satellites are by far the norm rather than the exception for KBOs, eh?

Guess this makes sense. There's nowhere near (by many orders of magnitude, probably) the amount of mutual tidal/gravitational interaction in the vastness of the KB as there is in the inner Solar System, so any leftovers after accretion of the main body would generally stay close; same thing applies to moons made of impact residue. The interesting question here is which of these two mechanisms is primarily responsible for KBO moon formation.