1995A&A...296..473H

Based on Coude spectra obtained with the 2.24-m telescope at MKO, we derive a map of the surface distribution of helium for the B9pSi star CU Vir. The helium abundance varies by more than one order of magnitude over the surface of this star and is concentrated in one large spot and a second, less pronounced, spot. This pattern is in anti-phase to the silicon surface distribution and is similar to what we have found for ET And, which is another Si-star. We compare our observed equivalent width measurements and synthetic ones, which we have derived from our map, with previously published data and can corroborate the long-term stability of the spots. CU Vir is the second CP2 star, for which a helium surface map is available.