The Fate of Icy Bodies Scattered from the Snowline in Systems without Giant Planets
Abstract
Recent studies show that for a large subset of circumstellar disks, the gas disk will dissipate before the planetary embryos are able to grow into gas giants. We present the results of simulations of planetary systems investigating this scenario. Each simulation begins after the nebular gas has disappeared and oligarchic protoplanets have begun to grow from a disk of planetesimals with a mass concentration at a hypothetical "ice line" at 5-6 AU. We investigate systems with different (i) mass fractions (f) in oligarchs, and (ii) degrees of dynamical "over packing" (oligarchic spacing b in Hill radii) in the ice line. 30 of the 40 simulations were run with b = 2 and f = 0.25, 0.50, and 0.75. Although the simulations are highly chaotic at early times, the oligarch mass fraction affects both the stability and mass distribution of the system. Higher initial embryo fractions produce systems that are less chaotic, and have more evenly spaced planets. Further, we investigate the feasibility of detecting such bodies by microlensing and direct imaging of hot protoplanets after major collisions. We find that protoplanets that reach stable orbits at 2-6 AU are the most likely to be detected by microlensing. These bodies constitute 28% of the resulting oligarchs and at least one is present in 82% of systems. 10 of the 40 simulations were run f = 0.04 and b = 8 (an unpacked ice line) for comparison.
- Publication:
-
American Astronomical Society Meeting Abstracts #215
- Pub Date:
- January 2010
- Bibcode:
- 2010AAS...21542306M