Hertzsprung-Russell diagram of the observed Galactic WC and WO stars with updated luminosities due to Gaia distances. The samples are taken from Sander et al. (2019). Hertzsprung-Russell diagram with the evolutionary track of the massive models with the different types/phases marked in colours (Before WR stars: black; WNL: red; WNE: pink; WC: green; WO: cyan). The range for the observed late WC stars with low luminosity is marked by a box. Panel a: single star models. Panel b: single star model S6. Panel c: rotating binary models.