Planetary migration in precessing disks for S-type wide binaries

TL;DR

This study investigates how the gravitational potential of a precessing protoplanetary disk in wide binary systems suppresses Lidov-Kozai resonance effects on migrating giant planets, influencing planet formation and spin-orbit alignment.

Contribution

The paper introduces new formulas for disk precession in binary systems and demonstrates through extensive simulations how these effects inhibit Lidov-Kozai resonance during planet migration.

Findings

Disk forces keep planets aligned with the disk midplane.

Binary-induced precession suppresses Lidov-Kozai resonance.

Primordial spin-orbit misalignment can occur due to binary influence.

Abstract

The discovery of numerous circumprimary planets in the last few years has brought to the fore the question of planet formation in binary systems. The significant dynamical influence, during the protoplanetary disk phase, of a binary companion on a giant planet has previously been highlighted for wide binary stars. In particular, highly inclined binary companion can induce perturbations on the disk and the planets, through the Lidov-Kozai resonance, which could inhibit the formation process. In this work, we aim to study how the disk gravitational potential acting on the planet and the nodal precession \textbf{induced by the wide binary companion with separation of 1000 AU} on the disk act to suppress the Lidov-Kozai perturbations on a migrating giant planet. We derive new approximate formulas for the evolution of the disk's inclination and longitude of the ascending node, in the case of a rigidly precessing disk with a decreasing mass and perturbed by a wide binary companion, which are suitable for $N$-body simulations. We carry out 3200 simulations with several eccentricity and inclination values for the binary companion. The gravitational and damping forces exerted by the disk on the planet tend to keep the latter in the midplane of the former, and suppress the effect of the binary companion by preventing the planet from getting locked in the Lidov-Kozai resonance during the disk phase. We also confirm that because of nodal precession induced by the binary, a primordial spin-orbit misalignment could be generated for circumprimary planets with an inclined binary companion.