Published online by Cambridge University Press: 04 August 2017
The evolution of planetary nebula (PN) nuclei has been studied at masses of 0.60, 0.70 and 0.76 M⊙, and for the ejection of the PN at various phases of a helium shell flash cycle. The evolution at high luminosities takes longer for nuclei resulting from PN ejection at shell flash peak than it does for those resulting from ejection in the inter-flash phase. Comparison of our calculations with various observational results does not allow us to reach any definite conclusions regarding the phase of the shell flash cycle at which PN ejection occurs.