∆v_rad (left) and σv_rad (right) distributions for the O-type stars in our initial sample not identified as SB2s and having a v sin i≤ 180 km s⁻¹. We indicate with different colors how the stars were finally classified as C/LPV/SB1 in the stars with more than one spectrum. Horizontal dashed lines indicate the thresholds considered to separate the stars in the three categories. For most stars, both indicators coincide. In case of divergence, the higher variability flag prevails (SB1, then LPV, and then C).