The long-term brightness variations of HD 123351. The top panel shows our twelve years of V-band photometry (dots), the lower panel plots the corresponding V − I color index. The lines are the seasonal fits of the two-spot models from Sect. 4. These models are plotted here as spherical projections at four different phases (from top to bottom, 0°, 90°, 180°, 270°). The gray scale indicates the spot temperature. Note the rotational modulation with a period of  ≈ 60 d and a long-term variation in both V and V − I in the sense that the star appears redder when fainter.