Oligarchic Growth in Outer Solar System
(Thommes, Duncan, & Levison 2002)

• The cores of Jupiter and Saturn must form before the gas disk goes away, which is about ~10⁷yrs.
  
  
• The cores must be ~10 to accrete gas from solar nebula.
  
  
• Our models of oligarchic growth predict that cores can grow in this time if disk mass ~5X minimum mass nebula.
  • However, not much happens at 20-30AU.
• There is ~ 70 of solids in this region.
• Cores are about 10-15 4-5 cores.

4 cores between ~4AU and ~10AU in gas disk.