Giant fields of small stars. New insights into M-dwarf magnetism

by Oleg Kochukhov (Uppsala University)

Wednesday 17 Feb 2021, 13:30 → 14:30 Europe/Stockholm

https://stockholmuniversity.zoom.us/j/530682073

https://stockholmuniversity.zoom.us/j/530682073

Magnetic fields play a fundamental role for interior and atmospheric properties of M dwarfs and greatly influence terrestrial planets orbiting in the habitable zones of these low-mass stars. Determination of the strength and topology of magnetic fields, both on stellar surfaces and throughout the extended stellar magnetospheres, is a key ingredient for advancing stellar and planetary science. In this talk I will review modern methods of magnetic field measurements applied to M dwarfs, with an emphasis on direct diagnostics based on interpretation of the Zeeman effect signatures in high-resolution intensity and polarisation spectra. I will summarise results of mean field strength measurements derived from Zeeman broadening analyses as well as information on global magnetic geometries inferred by tomographic mapping technique. The emerging understanding of complex, multi-scale nature of M-dwarf magnetic fields is discussed in the context of theoretical models of hydromagnetic dynamos and stellar interior structure altered by magnetic fields.

Kochukhov_2021_Feb_17.mp4