Evolution of massive population 2 stars with semi-convection

We present evolutionary tracks for mass-conserving 12 and 32 Msub(sun) stars (including the effects of semi-convection) as a function of initial composition (X=0.7, Z=0.02; X=0.7,Z=0.0004; X=0.78,Z=0.0004). Low-Z stars are bluer, brighter, have larger convective cores, and ignited He nearer the main sequence than high-Z stars. Many of these effects are partially compensated when the helium abundance is also lowered. The most striking effect of semi-convection is in increasing the main sequence lifetime by 20-30%. None of these results is quantitatively new, despite the use of a completely independent evolutionary code, suggesting that our understanding of massive star evolution through carbon burning is now fairly complete. (author)