The Turbulent Origin of Spin-Orbit Misalignment in Planetary Systems

TL;DR

This paper shows that turbulence during star formation can naturally cause misalignments between stellar spin and protoplanetary disks, explaining observed hot Jupiter obliquities without requiring post-formation migration mechanisms.

Contribution

It introduces hydrodynamic and magnetohydrodynamic simulations along with a semi-analytic model linking turbulence to stellar obliquity, providing a new explanation for spin-orbit misalignments.

Findings

Turbulence can produce a wide range of stellar obliquities.

Simulation results match observed hot Jupiter obliquity distribution.

Misaligned hot Jupiters may migrate via disk tidal dissipation.

Abstract

The turbulent environment from which stars form may lead to misalignment between the stellar spin and the remnant protoplanetary disk. By using hydrodynamic and magnetohydrodynamic simulations, we demonstrate that a wide range of stellar obliquities may be produced as a by-product of forming a star within a turbulent environment. We present a simple semi-analytic model that reveals this connection between the turbulent motions and the orientation of a star and its disk. Our results are consistent with the observed obliquity distribution of hot Jupiters. Migration of misaligned hot Jupiters may, therefore, be due to tidal dissipation in the disk, rather than tidal dissipation of the star-planet interaction.