Calculated models of proto-He WDs from Fig. 2 for M₂ = 1.2 M_⊙ (orange) and M₂ = 1.4 M_⊙ (blue). The black line is a fit to the data. It can also be derived analytically using a modified core mass-luminosity relation for low-mass evolved stars, combined with an assumed fixed amount of residual hydrogen (0.01 M_⊙) to be burned. The red line separates models with and without flashes.