Planetary Nebula/White Dwarf Stars – Little Ghost Nebula. Some red giant stars develop into planetary nebulas as their cores continue to contract, to increase in temperature, and to burn and vent the remaining gases into interstellar space. Eventually, the core collapses to the point where it is hot enough to ionize the vented gases, forming a relatively short-lived (~10,000-20,000 years) planetary nebula. The remaining core collapses into a white dwarf star. The vented materials from the planetary nebula play an important role in enriching the universe in elements with atomic weights less than 26 (forming the basis for carbon-based life like ourselves!). Which type of star will form a planetary nebula? Choose one: high-mass star (greater than 8x the mass of our Sun) intermediate- to low-mass stars (between 0.8x to 8x the mass of our Sun)