Orbital Stability of Circumstellar Planets in Binary Systems

TL;DR

This study uses extensive N-body simulations to map the stability zones of planets orbiting one star in binary systems, providing practical tools for exoplanet detection and characterization.

Contribution

It offers a comprehensive analysis of circumstellar planet stability in binary systems and provides interpolation tools for the community to assess stability limits efficiently.

Findings

Planets within ~8% of the binary separation are likely stable.

Stability limits vary with orbital inclination and regime, such as Lidov-Kozai.

Results aid in interpreting exoplanet observations with JWST, TESS, and Gaia.

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 thus understanding conditions on their stability is of great importance in exoplanet searches. We perform $\sim$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 $a_p$ $\lesssim$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 JWST, photometry with TESS, or even astrometry with Gaia.