Clues to the origin of Jupiter

1
Clues to the origin of Jupiters Trojans the
libration amplitude distribution

• F. Marzari, P. Tricarico, and H. Scholl
• Katie McGleam
• TERPS conference Dec. 7, 2004

2
Outline

• Background
• Trojan origin
• Mutual Collisions
• Mass Growth of Jupiter
• Combination
• Dynamical Instability
• Put it all together!

3
Background

• Trojans orbit at the stable L4 and L5 points of
  Jupiter.
• Estimated that there are about half as many
  Trojans as main belt asteroids.
  (Shoemaker et al, 1989)
• Libration amplitudes

Minor Planet Center Plot prepared on 1997
March 7
4
Capture Mutual Collisions

• Model
• Sun, Jupiter, Saturn
• 5000 planetesimals
• a 4.9 5.5 AU, e 0.0 0.1, i 0-1.5
• Jupiter Saturn fixed mass of 10 M?
• Results
• 450 captured, 54 with D lt 40

5
Capture Mass Growth of Jupiter

• Model
• same as before, except
• Jupiter and Saturn grow at the same rate from 10
  M? to
• their present sizes over 2x104 years.
• no collisions
• Results
• 1850 captured, all with D gt 40, most would be
  unstable

6
Mutual Collisions Mass Growth

• Model
• Two stages
• 1. Collisions only, 2x104 years, Jupiter
  Saturn
• fixed mass of 10 M?
• 2. Mass growth over another 2x104 years, with
  collisions
• Results
• 346 captured, 67 with D lt 40

Shaded region captured before mass growth
7
Add Dynamical Instability