The Role of Planetesimal Driven Migration (cont)
- This type of migration occurs in roughly 10-20% of our simulations without fragmentation.
- Might be higher if we included a size-distribution for embryos.
- No Type I in these simulations.
- Although in experiments with one planet, planetesimal driven migration trumps Type I.
- Ex: Mars-mass object in MMSN, 1 km planetesimals.
- Even when inward, planets migrate much faster than Type I.
- See poster by Capobianco et al.
- However, aerodynamic drag + resonant trapping usually dominates.
- Thus, must avoid having many objects at ~100m! We can think of two ways:
- Planetesimals are very strong.
- Primative planetesimals are pulverised when they break.
- Consistent with lack of primitive asteroid families (Nesvorny et al.).
- Also with the dearth of small impactors in Europa (Bierhaus et al.).
