UX Ari: new photometry and longitudinal asymmetry in spot activity fixed in orbital reference frame

Abstract

We present new BV photometry of UX Ari obtained on 23 nights during January-March 2008. From an analysis of the long-term V band photometry available for this star we find strong evidence for the orbital modulation of spot activity in the cool component of UX Ari: the hemisphere facing the companion shows a higher level of spot activity, as indicated by a significantly larger spread in observed brightness, when compared to that away from it.