Magnetic activity & prominence behaviour of the binary system V471 Tau

This poster presents the analysis of spectropolarimetric data of the pre-cataclysmic variable binary system V471 Tau obtained with ESPaDOnS at the Canada-France-Hawaii Telescope in two observational campaigns. We show first reconstructions of the large-scale magnetic field of the K2 dwarf, as well as new brightness maps and the amount of differential rotation by which surface maps are sheared. We compare the differential rotation fluctuations obtained for the K2 dwarf with those of the single-star analogue AB Dor. Finally, we argue that a slingshot mechanism likely sustains the prominence observed in 2004.