HR diagram with evolutionary tracks of Ekström et al. (2012) for rotating stars of solar metallicity. The different colours identify the different stages of the stellar evolution: thin black: pre-WR phase; thick yellow: WNL phase (i.e. with hydrogen between 40−5% mass fraction); thick green: WNE phase (hydrogen less than 5% mass fraction); thick blue: WC phase (i.e. carbon more than 20% mass fraction). The positions of WR 102c (blue diamond) and the OB-type stars (light blue squares) are indicated as well.