The turbulent environment from which stars form may lead to misalignment between the stellar spin and the remnant protoplanetary disc. 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 disc. 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 disc, rather than tidal dissipation of the star–planet interaction.
Drummond B Fielding, Christopher F McKee, Aristotle Socrates, Andrew J Cunningham, Richard I Klein. The turbulent origin of spin–orbit misalignment in planetary systems. MNRAS, 481(3):3325–3347, May 2015