2000MNRAS.318.1171K

We present a model for the differential rotation and dynamo activity of the young rapidly rotating K0 dwarf LQ Hya (P_rot=1.6d). As might be expected from observations of the similar rapid rotator AB Dor, the predicted differential rotation is small (≃0.8per cent) but extremely efficient in generating magnetic fields. The dynamo, which is of a distributed type, produces a globally axisymmetric field with radial and azimuthal components that are of the same magnitude and display a phase-lag in their evolution of about π/2. This is consistent with the long-term Zeeman-Doppler imaging study by Donati. The latitudinal distribution of flux is, however, a little different from that observed and the cycle period of 3.2yr is somewhat shorter than suggested by the observations.