Solar-like dynamos and rotational scaling of cycles from star-in-a-box simulations

TL;DR

This study uses star-in-a-box magnetohydrodynamic simulations to explore solar-like magnetic cycles and differential rotation, revealing insights into stellar dynamo behavior and rotational scaling that differ from traditional models.

Contribution

It introduces a novel simulation approach that includes the radiative core, providing new perspectives on stellar dynamos and magnetic activity patterns.

Findings

Simulations produce solar-like differential rotation with a fast equator.

Magnetic activity shows equatorward migration similar to the Sun.

The ratio of rotation to cycle period remains nearly constant across different rotation rates.

Abstract

Magnetohydrodynamic star-in-a-box simulations of convection and dynamos in a solar-like star with different rotation rates are presented. These simulations produce solar-like differential rotation with a fast equator and slow poles, and magnetic activity that resembles that of the Sun with equatorward migrating activity at the surface. Furthermore, the ratio of rotation to cycle period is almost constant as the rotation period decreases in the limited sample considered here. This is reminiscent of the suggested inactive branch of stars from observations and differs from most earlier simulation results from spherical shell models. While the exact excitation mechanism of the dynamos in the current simulations is not yet clear, it is plausible that the greater freedom that the magnetic field has due to the inclusion of the radiative core and regions exterior to the star are important in shaping the dynamo.