Stellar magnetic fields could explain unusual exoplanet orientations

New Scientist : Some of the exoplanets that have been found in recent years have orbits that don’t align with their star’s axis of rotation. Some planets even orbit their star in the opposite direction. Such misalignment is considered unusual because it has been assumed that planets form from the disk of material that rotates about the star. All of the unusual planets share one characteristic: They have parent stars at least 1.2 times the mass of the Sun. Based on that observation, Christopher Spalding of Caltech and his colleagues suggest that because smaller stars have stronger magnetic fields, they are more likely than heavier stars to be able to align their protoplanetary disks. According to Spalding and company’s calculations, the weaker magnetic fields of heavier stars cannot align a disk before it dissipates and the solar system forms.