Hidden dynamo spins down radiative stars

The life and death of a star are controlled by its internal rotation dynamics through subtle transport and mixing mechanisms, which so far remain poorly understood. While magnetic fields must play a crucial role in transporting angular momentum and chemical species, the very origin of magnetism in radiative stellar layers and its influence on spinning dynamics are yet to be unraveled. Using global numerical modeling, we report the existence of a dynamo sharing many characteristics with the (never observed) Tayler-Spruit model, which can generate strong magnetic fields and significantly enhance transport in radiative zones. The resulting, deep toroidal fields are screened by the outer medium, allowing for the existence of intense magnetism in radiative stars where no magnetic fields could be directly observed so far.