The stability of unevenly spaced planetary systems

Abstract

Studying the orbital stability of multi-planet systems is essential to understand planet formation, estimate the stable time of an observed planetary system, and advance population synthesis models. Although previous studies have primarily focused on ideal systems characterized by uniform orbital separations, in reality a diverse range of orbital separations exists among planets within the same system. This study focuses on investigating the dynamical stability of systems with non-uniform separation. We considered a system with 10 planets with masses of $10^{-7}$ solar masses around a central star with a mass of $1$ solar mass. We performed more than 100,000 runs of N-body simulations with different parameters. Results demonstrate that reducing merely one pair of planetary spacing leads to an order of magnitude shorter orbital crossing times that could be formulated based on the Keplerian periods of the closest separation pair. Furthermore, the first collisions are found to be closely associated with the first encounter pair that is likely to be the closest separation pair initially. We conclude that when estimating the orbital crossing time and colliding pairs in a realistic situation, updating the formula derived for evenly spaced systems would be necessary.

arXiv comment6 pages, 3 figures, accepted for publication in Icarus

References in corpus (13)

• REBOUND: An open-source multi-purpose N-body code for collisional dynamics
• Architecture and Dynamics of Kepler's Candidate Multiple Transiting Planet Systems
• IAS15: A fast, adaptive, high-order integrator for gravitational dynamics, accurate to machine precision over a billion orbits
• WHFast: A fast and unbiased implementation of a symplectic Wisdom-Holman integrator for long term gravitational simulations
• Breaking the Chains: Hot Super-Earth systems from migration and disruption of compact resonant chains
• Toward a Deterministic Model of Planetary Formation VII: Eccentricity Distribution of Gas Giants
• Post-Oligarchic Evolution of Protoplanetary Embryos and the Stability of Planetary Systems
• N-body simulations of planetary accretion around M dwarf stars
• Three Body Resonance Overlap in Closely Spaced Multiple Planet Systems
• Formation of close-in super-Earths in evolving protoplanetary disks due to disk winds
• The path to instability in compact multi-planetary systems
• Dynamical instability and its implications for planetary system architecture
• Ejection of close-in super-Earths around low-mass stars in the giant impact stage