* Astronomy

Title: Planetary system disruption by Galactic perturbations to wide binary stars
Authors: Nathan A. Kaib, Sean N. Raymond, Martin Duncan,

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.

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Wide binary stars study

Two simulations of planetary system disruption by galactic disturbances to wide binary stars. On the left is a zoomed-out view showing the orbit of a hypothetical 0.1 solar mass binary star around our own solar system with an initial orbital separation of 10,000 AU (1 AU is the distance between the Earth and the Sun). On the right is a zoomed-in view of the orbits of Jupiter, Saturn, Uranus, and Neptune. As the binary orbit becomes eccentric, this eventually excites the planetary orbits and Uranus and Neptune are both ejected.
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