The Basics of Trans-Neptunian Dynamics
Typically divided into two regions:
- Kuiper belt: Predicted in 1930, 1950,& 1988 (Duncan et al.), discovered 1992 (Luu & Jewitt)
- Traditionally 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))=9O .
- However, i'=21O if corrected for observational bias (Brown)!
- Scattered Disk: Predicted in 1997 (Duncan & Levison), discovered 1997 (Luu & Jewitt)
- Traditionally 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.
 Implies what we (I?) thought last year.