In this work the latitude dependent stellar spot rotation is investigated
based on dynamo models. The maps of the magnetic pressure at the surface from
the dynamo calculations are treated similarly to the temperature maps obtained
using Doppler imaging techniques. A series of snapshots from the dynamo models
are cross-correlated to obtain the shift of the magnetic patterns at each
latitude and time point. The surface differential rotation patterns obtained
from the snapshots of the dynamo calculations show in all studied cases
variability over the activity cycle. In the models using only the large scale
dynamo field the measured rotation patterns are only at times similar to the
input rotation law. This is due to the spot motion being mainly determined by
the geometric properties of the large scale dynamo field. In the models with
additional small scale magnetic field the surface differential rotation
measured from the model follows well the input rotation law. The results imply
that the stellar spots caused by the large scale dynamo field are not
necessarily tracing the stellar differential rotation, whereas the spots formed
from small scale fields trace well the surface flow patterns. It can be
questioned whether the large spots observed in active stars could be caused by
small scale fields. Therefore, it is not clear that the true stellar surface
rotation can be recovered using measurements of large starspots, which are
currently the only ones that can be observed.Comment: 8 pages, 10 figures, accepted for publication in A&
