HR diagram of the models. The new tracks are plotted with a red-black-green colour gradient, with the indicated colour code: the mass fraction of the convective envelope is indicated in red, while that of the convective core is coloured in green. The black segments indicate fully radiative stars. The mass and accretion rate along the birthline are indicated at various stages. The blue curves are the non-rotating models of Ekström et al. (2012). The black dotted line is the ZAMS of Ekström et al. (2012). The grey straight lines are the iso-radii of the indicated radii.