Single-hemisphere dynamos in M-dwarf stars

Benjamin P. Brown*, Jeffrey S. Oishi, Geoffrey M. Vasil, Daniel Lecoanet, Keaton J. Burns

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

M-dwarf stars below a certain mass are convective from their cores to their photospheres. These fully convective objects are extremely numerous, very magnetically active, and the likely hosts of many exoplanets. Here we study, for the first time, dynamo action in simulations of stratified, rotating, fully convective M-dwarf stars. Importantly, we use new techniques to capture the correct full ball geometry down to the center of the star. We find surprising dynamo states in these systems, with the global-scale mean fields confined strongly to a single hemisphere, in contrast to prior stellar dynamo solutions. These hemispheric-dynamo stars are likely to have profoundly different interactions with their surroundings, with important implications for exoplanet habitability and stellar spindown.

Original languageEnglish (US)
Article numberL3
JournalAstrophysical Journal Letters
Volume902
Issue number1
DOIs
StatePublished - Oct 10 2020

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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