No CrossRef data available.
Published online by Cambridge University Press: 24 September 2020
Signs of stellar activity such as large surface spots and radio flares are often related to binarity. UX Arietis is one of the most active members of the RS CVn class of binaries in which spin-up of a sub-giant/giant star by a close companion leads to the creation of magnetic fields. UX Arietis exhibits these signs of activity, originating mostly on the K0 sub-giant primary component. We measured the orbit with the CHARA interferometer and made images of a single large spot rotating in and out of view over a month in 2012. The rotation of the stars is synchronous with the orbit, and long-term photometric observations show that the spot or spots do not move much during intervals of a year. Our aim is to relate the positions of the stars and the spots on the primary to astrometry of the radio components observed during outbursts.