Orbital Stability of Circumstellar Planets in Binary Systems

Abstract

Planets that orbit only one of the stars in stellar binary systems (i.e., circumstellar) are dynamically constrained to a limited range of orbital parameters, and understanding conditions on their stability is thus of great importance in exoplanet searches. We perform ∼700 million N -body simulations to identify how stability regions depend on properties of the binary, as well as the starting planetary inclination and mean longitude relative to the binary orbit. Moreover, we provide grid interpolation maps and lookup tables for the community to use our results. Through Monte Carlo methods, we determine that planets with a semimajor axis a p  ≲ 8% of the binary semimajor axis a bin will likely be stable, given the known distribution of binary star parameters. This estimate varies in the Lidov–Kozai regime or for retrograde orbits to 4% or 10% of a bin , respectively. Our method to quickly determine the circumstellar stability limit is important for interpreting observations of binaries using direct imaging with the James Webb Space Telescope , photometry with the Transiting Exoplanet Survey Satellite , or even astrometry with Gaia .