Some History
- The idea of a large population of objects beyond Neptune dates to
Leuschner and Leonard in the 1930's.
- The need for such a population was recognized because it was
required as a source of comets (Fernandez).
- Particularly, it was needed to explain the inclinations of the
Jupiter-family comets.
(Duncan, Quinn, & Tremaine)
- Median inclination only 11O.
- Also, it was needed to explain the origin of the Centaurs.
- On low-inclination planet crossing orbits beyond Jupiter.
- Dynamical lifetimes are very short, for example Chiron (Oikawa & Everhart).
- The basic idea was:
- Objects slowly leak out of the Kuiper belt. (Levison & Duncan, Holman & Wisdom)
- They get scattered by the planets.
Centaurs.
- Some enter the inner solar system Jupiter-family comets.
- Continued study of this process led to:
- prediction of the scattered disk (which turns out to be the source of Centaurs and JFCs).
- estimates of physical lifetimes of JFCs.
- ages of giant planet satellites' surfaces.
