The Basics of Trans-Neptunian Dynamics
Typically^[1] divided into two regions:

• Kuiper belt: Predicted in 1930, 1950,& 1988 (Duncan et al.), discovered 1992 (Luu & Jewitt)
  • Traditionally^[1] objects that are in primordial or nearly primordial orbits
    (i.e. not scattered by planet).
  • 380 objects, 182 with good orbits. These are large, roughly 100km.
  • Two types of objects:
    • Resonant objects mainly in the 2:3 mean motion resonance with Neptune,
      also in 3:4, 3:5, and 1:2.
      • roughly 4% of population (biases corrected). (Trujillo et al.)
    • `Main belt':
      • Inner edge @ ~40AU, outside the 2:3 resonance.
      • Outer edge @ 50AU? There is currently much debate whether this is real or not.
      • Inclinations very large, observed i'=cos^-1(mean cos(i))=9^O .
        • However, i'=21^O if corrected for observational bias (Brown)!
  
  
• Scattered Disk: Predicted in 1997 (Duncan & Levison), discovered 1997 (Luu & Jewitt)
  • Traditionally^[1] thought to be objects that were gravitationally scattered by Neptune.
  • 40 objects, 25 with good orbits.
  • Largest known a is 228AU. These are large, roughly 100km.
  • Should have perihelion distances near Neptune.

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^[1] Implies what we (I?) thought last year.