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Colloquium
Dancing with the binary: diverse orbital dynamics and stability around circumbinary systems

Abstract

Recent observations have revealed that circumbinary disks misaligned to the binary orbit could be common in the universe. Dissipation in the disc causes it to move either towards coplanar alignment or polar alignment. In the polar configuration, the disc is perpendicular to the binary orbit, with the disc angular momentum vector aligned to the binary eccentricity vector. Since planets form inside disks, circumbinary planets may also form misaligned to the binary orbit. We explore the dynamical evolution and stability of misaligned circumbinary planets. We find that around eccentric binaries, the most stable orbits are those that are close to a polar alignment. Moreover, we find that two circumbinary planets in the same system may result in complicated orbital dynamics and resonances. These interactions could efficiently lead to the formation of free-floating planets because hosting multiple planets around a binary is more challenging than in a single star system.