Planetary System Disruption Within Wide Binary Star Systems

Because they are so weakly bound, the orbits of wide binary stars evolve greatly under the influence of the Galactic tide and impulses from passing field stars. Most systems eventually pass through phases of high eccentricity, and this can have catastrophic consequences for the planets orbiting within these binary systems. During these eccentric phases, close encounters between the two binary members occur, and any planets orbiting the stars can be strongly perturbed. We use numerical simulations to study the planetary dynamics within such wide binaries, and we find that dynamical instabilities are common. For planetary configurations like our own solar system, we find that a wide binary companion (a > 1000 AU) will trigger planetary ejections in 1/3 to 1/2 of all systems. Interestingly, these ejections and instabilities typically occur only after hundreds of Myrs or Gyrs of evolution, possibly generating events similar to the LHB instability that occurred in our own solar system