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Context. Surface differential rotation and other global surface flows onmagnetically active stars are among the observable manifestations of thestellar dynamo working underneath. Therefore, such observations are importantfor stellar dynamo theory and useful constraints for solar dynamo studies aswell.  Aims. The active K1-giant component of the long-period RS CVn-type binarysystem sigma Gem and its global surface flow pattern is revisited.  Methods. We refine the differential rotation law from recovering the spotmigration pattern. We apply a detailed cross-correlation technique to a uniqueset of 34 time-series Doppler images recovered using data from 1996/97. Byincreasing the number of the available cross-correlation function maps from theformerly used 4 to 17 we expect a more robust determination of the differentialsurface rotation law. In addition, we present a new time-series Doppler imagingstudy of sigma Gem using our advanced surface reconstruction code iMap for adataset collected in 2006/07.  Results. Results from the reprocessed cross-correlation study confirm thatthe star performs antisolar-type differential rotation with a surface shearalpha of -0.04 +/- 0.01, i.e., almost a factor of two stronger compared to thepreviously claimed value. We also confirm the evidence of a global polewardspot migration with an average velocity of 0.21 +/- 0.03 km/s, in accordancewith theoretical predictions. From the new observations we obtain threesubsequent Doppler images. The time evolution of these images confirms theantisolar-type differential rotation of the same amount.

Antisolar differential rotation of the K1-giant sigma Geminorum revisited