Capturing the Oort Cloud from Other Stars
(Levison, Duncan, Brasser, & Kaufmann 2010)
- Need star clusters because densities are high and velocities small.
- Most (All?) stars form in (embedded) clusters.
- Clusters where stars form typically:
- Contain ~10 — ~1000 stars.
- Radii between ~0.1 and ~1 pc. Not that different from the size of the Oort cloud.
- Between 70% and 90% of mass is in gas.
- But, gas is removed after a few Myr by supernovae and strong stellar winds.
- Very fast once these processes turn on (i.e. when the massive stars get old).
- Causes cluster to explode.