Oligarchic Growth with Migration and Fragmentation
Abstract
In the core-accretion model for giant-planet formation, large solid cores form via runaway and oligarchic growth from a population of small planetesimals. Once a core reaches roughly 10 Earth masses, it can begin to accrete a gaseous envelope provided that gas is still present in the protoplanetary disk. High-velocity collisions between planetesimals generate small fragments. Interactions between a core and the surrounding gas disk can cause rapid inward planetary migration. Fragmentation and migration each have positive and negative effects on the formation of giant-planet cores. Small fragments are accreted more quickly than large planetesimals, speeding up growth. However, fragments drift inwards rapidly and can be lost. Migration allows a core to grow beyond its isolation mass by moving into new regions of the disk. However, cores can also be lost if migration rates are high. Here, I will describe results of new simulations of giant-planet core formation including migration and fragmentation. I will show that fragmentation usually aids growth. Migration at nominal rates typically, but not always, prevents the formation of giant-planet cores.
- Publication:
-
AAS/Division for Planetary Sciences Meeting Abstracts #40
- Pub Date:
- September 2008
- Bibcode:
- 2008DPS....40.5807C