The Formation of Uranus and Neptune: The Standard Model

• In the Standard Model, the final accumlation of Uranus and Neptune is the result of collision between Lunar/Earth-mass objects.
  • Known as Late-Stage formation
  • Fernandez & Ip build Uranus and Neptune in < 2x10⁷ years.
    • Used a Monte Carlo, Öpik code.
  • Brunini & Fernandez `confirm' these results with direct N-body calculations.
  
  
  
• The published works on the late stage of Uranus and Neptune formation are wrong.
  • The authors of these papers now acknowledge that there were problems with their codes.
  • When we attempted to reproduce these, we get very little growth. (Levison & Stewart 2001).
    • In Ip 1989 simulation we got one merger in 10⁸ years!
    • Used the direct N-body code SyMBA.
      • Which is an extension of the Wisdom-Holman Mapping.
  • System got too `hot' to form planets.