Magnetic cycle of LQ Hydrae: observational indications and dynamo model

We present a model for the differential rotation and dynamo activity of the young rapidly rotating K0 dwarf LQ Hya (P-rot=1.6 d). As might be expected from observations of the similar rapid rotator AB Dor, the predicted differential rotation is small (similar or equal to0.8 per 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 pi /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 3.2 yr is somewhat shorter than suggested by the observations.