Type II Planetary NebulaeType II planetary nebulae have abundances characterized by intermediate mass stars or, more specifically, less massive stars than those producing Type I planetary nebulae. There are more stars capable of producing Type II planetary nebulae as compared to Type I.
The heavier elements processed within the stellar core are mixed with the lighter elements that make up the outer envelope of the star through a series of convection events called dredge-up (Bryce et al. 1994). Dredge-ups are the reason that planetary nebulae are an important part of chemical enrichment of the interstellar medium. |