9–13 Mar 2015
Albanova, Stockholm
Europe/Stockholm timezone

MHD simulations of sunspots and starspots with MURaM

10 Mar 2015, 17:20
20m
Oskar Klein Auditorium (Albanova, Stockholm)

Oskar Klein Auditorium

Albanova, Stockholm

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)

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