Evolution of Red Giant Stars

What triggers the transformation of a red giant's inert, helium-rich core?

Is the core sustainable in its current state?

Answer:

The transformation of a red giant's inert, helium-rich core is triggered by the depletion of helium fuel which leads to gravitational collapse.

Red giant stars evolve through different stages as they age. One of the key transformations that take place in a red giant is the evolution of its core.

The inert, helium-rich core of a red giant undergoes transformation when it depletes its helium fuel, which is used as the primary element for fusion reactions in the core. As the star exhausts its helium, there is no longer enough energy generated through fusion to counterbalance the force of gravity.

As a result, the core begins to contract due to gravitational collapse. This contraction initiates the transformation process, converting helium into heavier elements such as carbon and oxygen. The core continues to shrink as it converts helium to these new elements, eventually leading to the formation of different layers within the core.

Although the core experiences brief stability during the conversion of helium to carbon and oxygen, this phase is not sustainable in the long term. The lack of fusion energy production ultimately causes the core to shrink further, driving the star closer to the end of its life cycle.