What phase follows the red supergiant stage in massive stars?

The red supergiant stage is a late phase in the life cycle of massive stars, typically occurring after they have exhausted the hydrogen in their cores and have begun to fuse heavier elements. At this point, the core contracts under gravity, leading to increased temperatures that allow for the fusion of elements up to iron. However, once the core accumulates sufficient iron, fusion ceases to produce energy, since iron fusion does not release energy.

When the core becomes too heavy to support itself against gravitational collapse, it leads to an imbalance that cannot be resolved. The outer layers of the star then collapse onto the core and rebound in a dramatic explosion known as a supernova. This event is significant because it not only marks the end of the red supergiant phase but also plays a crucial role in dispersing elements into the universe, contributing to the formation of new stars and planets. As such, the explosive supernova event is the natural progression following the red supergiant stage in the life of a massive star.