About the project
The project “Magnetic Activity of the Atmospheres of M-type Dwarf Stars” is funded by the Research Council of Norway for the period 2011-2014.
Summary
Dwarf stars of spectral type M, shortly referred to as “M-dwarfs”, are the most frequent stars in the universe. They are therefore of large interest for our understanding of stars, their role as host stars of extrasolar planets and for a wide range of topics including the chemical composition and evolution of the universe. Unfortunately, many properties of the atmospheres of these small and faint stars are poorly known. It is still under debate whether a global dynamo in the interior or rather a local dynamo at the surface generates the magnetic fields observed in M-dwarfs. The resulting magnetic activity is observed in form of radiation emitted from the stellar chromospheres.
Space telescopes like Kepler and the future GAIA provide high-quality data, which will allow for characterizing the properties of M-dwarf atmospheres and their activity. A systematic set of realistic theoretical models is essential for a meaningful interpretation of the observations but does not exist so far.
The primary aim of this project is therefore the production of a small grid of 3-D models and synthetic spectra, which can be compared to data from ground-based and space-borne observatories.
Objectives
Understand the distribution and generation of magnetic fields in M-dwarf atmospheres and their imprint in chromospheric diagnostics.
Methodology
- time-dependent numerical simulations (3-D radiation magnetohydrodynamics in a local setup)
- radiative transfer calculations for the production of stellar spectra and intensity maps
- detailed comparison to observations