LAUSR

Stellar Activity The Sun's activity, including sun-spot activity, varies on an 11-year cycle driven by changes in its magnetic field. Other nearby solar-type stars have their own cycles, but the Sun does not seem to match their behavior. Strugarek et al. used magnetohydrodynamic simulations to show that stellar activity periods should depend on the star's Rossby number, the ratio between the inertial and Coriolis forces. Turning to observations, they found that solar-type stars, including the Sun, follow this relation. The results advance our understanding of how stars generate their magnetic fields and confirm that the Sun is indeed a solar-type star. Science , this issue p. [185][1] [1]: /lookup/doi/10.1126/science.aal3999