Formation of polar terrestrial circumbinary planets

TL;DR

This study uses simulations to explore the formation and stability of polar terrestrial planets around eccentric binaries, suggesting such planets are more likely to form in polar alignments and remain stable over time.

Contribution

It demonstrates through simulations that polar terrestrial planets can form and remain stable around eccentric binaries, expanding the understanding of possible planetary system configurations.

Findings

Polar terrestrial planets are more likely to form around eccentric binaries.

Polar planetary systems are stable even with general relativity effects.

Tilt and eccentricity oscillations are larger in coplanar systems.

Abstract

All circumbinary planets currently detected are in orbits that are almost coplanar to the binary orbit. While misaligned circumbinary planets are more difficult to detect, observations of polar aligned circumbinary gas and debris disks around eccentric binaries suggest that polar planet formation may be possible. A polar aligned planet has a stable orbit that is inclined by 90 degrees to the orbital plane of the binary with an angular momentum vector that is aligned to the binary eccentricity vector. With n- body simulations we model polar terrestrial planet formation using hydrodynamic gas disk simulations to motivate the initial particle distribution. Terrestrial planet formation around an eccentric binary is more likely in a polar alignment than in a coplanar alignment. Similar planetary systems form in a polar alignment around an eccentric binary and a coplanar alignment around a circular binary. The polar planetary systems are stable even with the effects of general relativity. Planetary orbits around an eccentric binary exhibit tilt and eccentricity oscillations at all inclinations, however, the oscillations are larger in the coplanar case than the polar case. We suggest that polar aligned terrestrial planets will be found in the future.