Activity variation driven by flux emergence and transport on Sun-like stars

In G dwarfs, the surface distribution, coverage and lifetimes of starspots deviate from solar-like patterns as the rotation rate increases. We set up a numerical platform which includes the large-scale rotational and surface flow effects, aiming to simulate evolving surface patterns over an activity cycle for up to 8 times the solar rotation and flux emergence rates. We assume a solar projected butterfly diagram at the base of the convection zone, and follow the rotationally distorted trajectories of thin flux tubes to obtain latitudes and tilt angles of emerging bipolar magnetic regions. Using them as source distributions, we run a surface flux transport model with solar parameters. Our models predict surface distributions of both the signed radial fields and starspots, which qualitatively agree with observations.