Eccentricities and the stability of closely-spaced five-planet systems

Observations of exoplanets have revealed that systems with planets on closely-spaced orbits are common, which motivates the question “How closely can orbit to one another and still be dynamically-stable for very long times?”. To address this question, we investigate stability idealized planetary consisting five planets, each equal in mass Earth, orbiting a solar star. All same plane direction, uniformly spaced units mutual Hill Sphere radii. Most integrate begin or more eccentric orbits, eccentricities e as large e=0.05 being considered. For given initial orbital separation, larger eccentricity single planet generally leads shorter system lifetime, little systematic dependence is initially an orbit. The approximate trend instability times increasing exponentially separation found previously circular also present orbits. Mean motion resonances tend destabilize these systems, although reductions lifetimes not Systems all having aligned periapse angles typically survive far longer than spacing semi-major axis e=0.05, but they slightly those