1994A&A...291..110O

UBV(RI)_C photometry of the short period RS CVn binary ER Vul, gathered in the years 1990-1992, is analysed. A set of binary system parameters is finally derived with some confidence, after due tests and comparisons with literature values. The well-known irregularities of ER Vul are interpreted largely in terms of dark maculae, whose major characteristics (size, surface position) are quantified. The occurrence of at least one bright spot (facula) is also evidenced, however. The maculation representation is shown to be consistent with a "quasi-poloidal" spot distribution - high latitude spot concentrations tending to be roughly symmetric in both hemispheres. This model requires further observational checking.