The 4¹/₂ Steps of Terrestrial Planet Formation in the Solar System. (cont) Step III: Oligarchic Growth (Kokubo & Ida 1998)

• Recall that as long as is not affected by M.
• As the big guys grow, they have a larger fraction of system mass stir small guys.
• So, growth slows.
• Studies have shown that (Kokubo & Ida):
  • The largest few objects at any given time are:
    1. of comparable mass
    2. separation is ~10R_H, (Earth: R_H=0.01AU)
       where R_H is the gravitational sphere of influence and is f(M,a).
  • So, as the system evolves:
    1. Number of big guys decreases.
    2. Their masses increase.
    3. Their separation increases.

---

Step IV: Late Stage (Wetherill, Chambers, Agnor)

• As the number of small objects decrease embryos scatter each other
  all hell breaks lose.
• Massive transport of material, the whole systems communicates.
• I will spend the rest of the talk on this stage, but first I must talk about integrators.