Hydrostatic Evolutionary Sequences for the Nuclei of Planetary Nebulae

This paper describes a set of evolutionary calculations for nuclei of planetary nebulae. The properties of the nuclei are studied as a function of the following three input parameters: (1) mass of the nucleus, which is set equal to 0.60, 0.70, 0.76, and 0.89 M_sun;; (2) departure phase from the asymptotic giant branch (AGB), which is set at four equally spaced values within the helium shell flash cycle; and (3) mass loss, which takes a range of forms. The authors argue that every AGB star capable of producing a core mass greater than 0.86 M_sun; will produce a planetary nebula with a helium-rich nucleus. Such nuclei will evolve through the planetary nebula phase burning helium before cooling off to become non-DA white dwarfs.