Jörn Warnecke

TL;DR: In this paper, a chromospheric activity index, S-index, was measured for 304 main-sequence stars from archived high-resolution HARPS spectra, and the measured and archived S-indices were converted into the chromosphere flux ratio log R0 HK.

TL;DR: In this paper, the authors present results from simulations of rotating magnetized turbulent convection in spherical wedge geometry representing parts of the latitudinal and longitudinal extents of a star, and test the domain size dependence of their results for a rapidly rotating run with equatorward migration by varying the longitudinal extent of our wedge.

TL;DR: The Pencil Code is a highly modular physics-oriented simulation code that can be adapted to a wide range of applications, primarily designed to solve partial differential equations of compressible hydrodynamics but can also evolve Lagrangian particles, their coagulation and condensation, as well as their interaction with the fluid.

TL;DR: In this paper, the authors analyze a solution of a solar-like DNS that was evolved for roughly 80 magnetic cycles of 4.9 years and where epochs of irregular behavior are detected.

TL;DR: In this paper, the authors present results from four convectively driven stellar dynamo simulations in spherical wedge geometry, and show that the migration direction can be explained by an αΩ dynamo wave following the Parker-Yoshimura rule.