Stability of closely packed multiple exoplanetary systems
Abstract
There are more then 4000 exoplanets have been observed up to now and hundreds of multiple planetary systems among them. Many planet pairs are in the configuration of mean motion resonances (MMRs) or near MMRs. We investigate the stability of multiple planetary systems to find out if the MMRs configuration is more stable for planets to survive. Through numerical simulation on equal-mass multiple planetary systems, we find out that (1) If all planets undergo inward type I migration, planet pairs tend to be more stable with the increase of the relative separation between them; (2) If there are both inward and outward migration exist in the system, the separation between planet pairs will shrink to smaller Hill Radius and planet pairs can find their stable configuration if they are captured into MMRs. But the stable region is very narrow; (3) The density of the gas disk is related to the final separation between planet pairs and when they are captured into MMRs. If planet pairs migrate to small separation with larger gas density, the system are easy to be crossing. The resonances are deeper in the system with larger depletion timescale and the system are more stable (4) When the libration timescale of planet pairs larger than the migration timescale which are caused by the mass loss of planets in the system, the stable configuration can be destroyed.
- Publication:
-
AAS/Division for Extreme Solar Systems Abstracts
- Pub Date:
- August 2019
- Bibcode:
- 2019ESS.....431805W