Wind-lifetime ratio vs. mass of a 17 M_⊙ star at different metallicities. The axes are the same as those in Fig. 1 and the right panel of Fig. 2. This plot combines the 17 M_⊙ tracks previously shown in Fig. 1 (at 5 Z_⊙ and 9 Z_⊙) with the 3 Z_⊙ model. The crossover masses decrease with increasing metallicity (see text). The first 2 million years of evolution have been excluded for plot clarity.