Left panel: variability indicator vs. IR excess in the range 1.24 − 22 μm. It can be seen how objects with the lower IR excess do not show high variability. Right panel: variability indicator vs. estimated mass. It can be seen how the most massive objects (more massive than ∼7 M_⊙) barely show any variability. Line profiles and temperatures are colour coded in the legend in the left and right panels, respectively. The symbols stand for the Hα line profiles: circles (double-peaked), triangles (single-peaked), stars (P-Cygni profile) and diamonds (no information). The V_i = 2 and V_i = 5 values are stressed for clarity.