Speaker
Benjamin Beeck
(Max Planck Institute for Solar System Research)
Description
The existence of starspots on cool main-sequence stars other
than the Sun is known from observations. However, the
properties of these spots (their sizes, temperature,
magnetic field strength, etc.) are not well constrained. We
aim at determining some of these properties in two- and
three-dimensional radiative MHD simulations of the
near-surface layers in a local-box setup. In a first
parameter study, we try to reproduce the observed properties
of sunspots starting from various initial conditions. We
find that a homogeneous and vertical magnetic field of up to
4kG is not sufficient to suppress the onset of vigorous
convection. Only simulations with a substantial vertical
gradient in the magnetic field and with field strengths of >
6 kG at a depth of a few Mm below the surface reproduce the
observed surface properties of sunspots. This is evidence
against sunspots being shallow structures. We will now apply
the same numerical setup to other cool main-sequence stars.
Primary author
Benjamin Beeck
(Max Planck Institute for Solar System Research)
