Over a timespan of 4.7 h the shape of m₁’s line cycles from paraboloid, to flat-bottomed, to sloping upward towards the blue and then approaching once again the paraboloid shape. Time runs from bottom to top in units of days and is indicated on the right side. The corresponding orbital phase is listed on the left. The profile shown with dashes is always the same one (φ = 0.34). The profile of m₂ appears here at −280 km s^-1.