Individual H band (left) and K band (right) spectra for massive stars. Labels indicate the object’s ID (H-band spectra) and spectral type (K band spectra). This set includes early-type stars with luminosity classes I, III, and V, and two Wolf−Rayets. The spectral features used for the spectral classifications are labelled in grey. The bottom red spectrum plotted over spectrum29 corresponds to WR62-2, a WN8-9h object (Chené et al. 2015) shown for visual comparison with the new Wolf−Rayet star WR122-16. The red supergiant spectrum is shown in Fig. 5.