2001MNRAS.326.1489L

We present narrow-band red light curves and surface maps of the short-period RS CVn binary system XY UMa, obtained between 1997 January and 2000 March. The light-curve morphology of this system is known to vary on time-scales of a few days. We have used eclipse-mapping techniques to map the distribution of cool starspots on the surface of the primary star. The resulting maps show the continued evolution of spot features on time-scales of a few days to a week. By comparison with the images of Collier Cameron & Hilditch, we also find evidence for longer term trends, including a decline to an activity minimum during 1997 and a rise in activity during 1998-2000. We also find marginal evidence from the O-C ephemeris curves for a periodicity and a peak corresponding to the time of activity minimum.