UBV photometry of FK Comae

UBV photometry of the peculiar star FK Comae, obtained during the period January–June 1983, is presented. The amplitude of the photometric variation has raised with respect to the previous observations performed in 1981 and 1982, attaining about 0.18 mag in theV filter. Colour curves indicate that the star is redder at minimum light; this fact is consistent with both the models presented to explain the properties of FK Comae. A Fourier analysis of the light curves available in the literature has been performed; the phases of minimum and maximum light turn out to be noticeably stable in time. This fact is difficult to be reconciled with the hypothesis of dark spots that are observed to migrate in other active stars. Rather, it could be explained by the model of Walter and Basri (1982a, b), implying an extremely evolved Algol-type system accreting mass on its primary component.