Nucleosynthesis origin of PG 1159 stars, Sakurai's object and of rare   subclasses of presolar grains
  We discuss theoretical AGB predictions for hydrogen-deficient PG 1159 stars and Sakurai's object, which show peculiar enhancements in He, C and O, and how these enhancements may be understood in the framework of a very late thermal pulse nucleosynthetic event. We then discuss the nucleosynthesis origin of rare subclasses of presolar grains extracted from carbonaceous meteorites, the SiC AB grains showing low 12C/13C in the range 2 to 10 and the very few high-density graphite grains with 12C/13C around 10. 
R. Gallino, O. Straniero, E. Zinner, M. Jadhav, L. Piersanti, S.   Cristallo, S. Bisterzo
astro-ph.SR