Monday

Starspots are windows into a star’s internal dynamo mechanism. They encode information about the generation of stellar magnetic fields, their rise to the surface, and the subsurface flows they encounter. However, the manner by which bundles of magnetic field traverse the stellar interior to emerge at the surface is not especially well understood. In the solar context, insight into this process has been obtained by assuming the magnetism consists partly of idealized thin flux tubes (TFTs). Here, we present three sets of TFT simulations in rotating spherical shells of convection: one representative of the Sun, the second of a solar-like rapid rotator, and the third of a fully convective M dwarf. We comment on the ability of our solar simulations to reproduce sunspot observables such as emergence latitude, tilt angles following the Joy’s Law trend, and a phenomenon akin to active longitudes. Further, we compare the evolution of rising flux tubes in our (computationally inexpensive) TFT simulations to buoyant magnetic structures that arise naturally in global simulations of rapidly rotating convective dynamos. Both computational models complement each other, and demonstrate that convective motions and magnetic buoyancy work in concert to promote flux emergence. In our fully convective M dwarf simulations, the emergence of flux tubes deviate from the solar trend, favoring significant poleward deflection unless the differential rotation is sufficiently prograde or the magnetic field is strongly super-equipartition. Our results aim to provide a link between dynamo-generated magnetic fields, fluid motions, and observations of starspots along the lower main sequence.