Stellar number density distribution in the Kiel (T_eff–log g) diagram. Only 211 245 stars with S /N > 30 are shown. Also shown in the figure are the MIST stellar evolution tracks (Paxton et al. 2011; Choi et al. 2016) with [Fe/H] = –0.5 and V/V_c = 0.4. The initial stellar masses of the tracks are marked (in unit of M_⊙). The stars with log g > 5 and log T_eff > 4.2 are hot subdwarfs. The vertical stripe at log T_eff ~ 4.0 is an artifact for chemically peculiar stars (e.g., Ap/Bp stars and Am stars) whose log g have been underestimated as a consequence of masking the hydrogen lines for label determination.