Distribution of candidate stars with r-band S/N > 10 in the Kiel diagram. Stellar density is colour-coded on a logarithmic scale. Temperature cuts at 7100 K and 19 000 K are applied. Stars above the dashed red line represent artefacts from intrinsically hotter stars (T_eff ⩾ 20 000 K) and are excluded from further analysis. Grey curves show evolutionary tracks for stars with masses of 1.7, 2.0, 2.5, 3.0, 4.0, 5.0, and 7.0 M_⊙ from MIST (Paxton et al. 2011; Choi et al. 2016) models.