Hunting for anti-solar differentially rotating stars using the Rossby number. An application to the Kepler field

Vol. 667
7. Stellar structure and evolution

Hunting for anti-solar differentially rotating stars using the Rossby number. An application to the Kepler field

Contrary to solar rotation, antisolar rotation is characterized by slow equatorial rotation and fast polar rotation. Such a rotation profile has been found for decades in numerical simulations for high Rossby numbers but has never been unambiguously observed for cool solar-type stars on the main sequence. The authors have devised a theoretical formula to estimate fluid Rossby numbers from the effective temperature and the rotational period. The authors applied their approach and obtained a promising candidate, KIC 10907436, which probably has antisolar differential rotation. The developed method can be applied to Kepler or future PLATO missions, puts constraints on the link between rotation and magnetism, and deepens our understanding of dynamo theory and magnetic activity in the long run.