Asymptotic Giant Branch

The Asymptotic Giant Branch (AGB) is a late stage in the life of certain stars, typically between 0.8 and 8 times the Sun's mass. During this phase, the star's core has exhausted its fuel and is made of inert carbon and oxygen. Surrounding this core, the star has two fusion layers: one fusing helium into carbon and another fusing hydrogen into helium. The star expands significantly, becoming very luminous and large, often developing a thick surrounding shell of gas and dust. This phase marks the star's end of life, eventually leading to the shedding of outer layers and forming a planetary nebula, leaving behind a dense core called a white dwarf.