Starspot distributions on XY UMa during 1997–2000 from eclipse mapping |
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| Authors: | TA Lister A Collier Cameron RW Hilditch |
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| Institution: | School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS |
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| Abstract: | 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. |
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| Keywords: | stars: activity binaries: eclipsing stars: imaging stars: individual: XY UMa stars: late-type stars: magnetic fields |
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