post-AGB stars

Post-AGB stars are evolved stars that have finished fusing helium in their cores and are transitioning from the asymptotic giant branch (AGB) phase towards becoming planetary nebulae. During this stage, the star sheds its outer layers, creating a surrounding shell of gas and dust, while the core contracts and heats up. The star's surface temperature rises significantly, and it eventually brightens as the outer layers disperse. This phase marks the final stages of a star’s life leading to its transformation into a white dwarf, illuminating the expelled material as a planetary nebula.