Hertzsprung-Russell diagram of luminous stars in the SMC. Red dots represent sources from the B10 data set. Open dark red squares are red supergiants from Davies et al. (2018), where the T_eff is obtained using relations from Tabernero et al. (2018). We show the Wolf-Rayet stars (Hainich et al. 2015; Shenar et al. 2016, 2017) labeled with a ‘W’ and their identifying number. Whe they have an O-star companion that is brighter in the V-band, we show this instead (indicated by ‘(O)’). We also show evolutionary tracks of Schootemeijer et al. (2019) with a semiconvection parameter of α_sc = 10, and an overshooting parameter of α_ov = 0.33. Solid lines indicate hydrogen- and helium-core burning phases; dashed lines indicate the in between phase. The dash-dotted gray line shows the location of these models halfway through their main-sequence (MS) lifetime, t_MS.