The dynamics of the main (non-resonant) Kuiper belt also may support this idea.

• The main Kuiper belt is very excited.
  
  
• Most likely due to massive objects moving through the region.
  
  
• The Thommes et al. model can explain the a-e distribution of the main KB.
  • But, cannot quite explain inclinations yet .
  
  
• It may also explain the H-i distribution. (Levison & Stern 2001)
  • There is correlation a between inclination and absolute magnitude, H.
    • Big guys have higher i's!
  • Only 0.02% chance that the i-distribution of H<6.5 objects is the same as H>6.5.
  • Interpreted as superposition of a hot and cold population. (like Brown 2001)
    • Cold population has H>6.5 and i<5^O.
    
    
  • So how did this happen? ........... I can think of only one way:
    • Start with a cold disk.
      • Accretion occurs faster closer in so bigger objects are closer in.
    • A large object (say Neptune-sized) is delivered to the inner regions of disk,
      say with a perihelion distance of ~40AU.
    • Inner disk objects are scattered outward and then the planet moves on.
    • In the outer regions of the disk, the high i objects formed closer in, so can be larger.
    • Get a similar thing in the Thommes et al. simulations.