What happens to a massive star after it becomes a super red giant?

After a massive star expands into a super red giant, it undergoes dramatic changes in its structure and energy production. The core of the star contracts and heats up, allowing nuclear fusion to take place for heavier elements, leading to the formation of iron in the core. This process is critical because iron fusion does not yield energy; instead, it consumes energy, which eventually leads to instability within the star.

As the core becomes unable to support itself against gravitational forces due to the lack of energy production, it collapses under its own gravity. This catastrophic collapse can lead to two possible outcomes depending on the mass of the original star. If the remaining core has a mass greater than approximately three solar masses, the gravitational collapse can be so intense that it results in the formation of a black hole. Alternatively, if the core's mass is less, it may produce a neutron star—an incredibly dense object made primarily of neutrons.

This transition marks the end of the star's life cycle and explains why the right answer points to the formation of either a black hole or a neutron star after the period of being a super red giant. The other options presented do not align with the expected fate of a massive star at this stage in its lifecycle.