Giant Planet Migration
- The giant planets migrate when embedded in a disk (Fernandez & Ip; Hahn & Malhotra).
- Neptune goes outward because it is easier to feed things to Uranus than to kick them out.
- Malhotra (1995) argued that the Kuiper belt resonant population was due to this migration.
But,
- Jupiter's and Saturn's eccentricity are too small at the end.
- A generic problem with any migration scenario because of standard dynamical friction.
- It is also a problem when considering interactions with gas disks.
- Unless they had very large initial eccentricities, but
- It is hard to believe that such systems would be stable.
- It would have decimated the asteroid belt (Chambers & Cassen).
