Advanced evolution of massive stars. V. Neon burning.

The continued evolution of massive helium stars (massive stars approximated by a helium star of equivalent mass) of mass 4, 8, 16, and 32 M is studied through neon burning in the center and up to 0 + 0 ignition. A continued tendency toward convergence of structure and evolution for the most evolved central matter is noted. Neon burning and the neon flash are shown to be important stages in the evolution of the lower mass stars. The central regions of these stars evolve much faster than the mantle; consequently, the composition of matter in the mantle tends to become stationary compared to changes in the core during neon burning.