What occurs after a red supergiant in the life cycle of a massive star?

In the life cycle of a massive star, once it has evolved into a red supergiant, the next critical phase is its dramatic end as a supernova. A red supergiant is a stage that occurs after a massive star has exhausted the fuel in its core, leading to the fusion of heavier elements. As the core becomes increasingly unstable, it eventually can no longer support itself against gravitational collapse.

When the core collapses, temperatures and pressures soar, triggering a massive explosion that blows the outer layers of the star into space. This extraordinary event is what we observe as a supernova. It marks not only the death of the star but also plays a significant role in enriching the interstellar medium with the elements formed during the star's lifetime and during the explosion itself.

The other options do not accurately describe the immediate aftermath of a red supergiant's life cycle. For instance, the formation of a neutron star or a black hole can occur after the supernova event, depending on the mass of the core that remains after the explosion. A planetary nebula, on the other hand, is associated with less massive stars and does not pertain to the evolution of a massive star that has entered the red supergiant phase. Thus,