Fe-deficiency in H-deficient post-AGB stars due to n-capture   nucleosynthesis
  H-deficient post-AGB objects, e.g. PG1159 type star K1-16 and born-again AGB star Sakurai's object, have been reported to be significantly iron-deficient. We find that the iron deficiencies expected due to neutron-capture nucleosynthesis during either the progenitor AGB evolution and/or the neutron burst that occurs as a result of the rapid burning of protons during a post-AGB He-flash are generally in line with observations. 
Falk Herwig (1), Maria Lugaro (2) and Klaus Werner (3) ((1) University   of Victoria, Canada, (2) IoA, University of Cambrid...