The relation between chemical enrichment and core mass in planetary nebulae

James B. Kaler, George H. Jacoby

Research output: Contribution to journalArticlepeer-review


From innovative methods of analysis applied to data on planetary nebulae in the Magellanic Clouds, we derive the masses of 32 central stars, the nebular nitrogen and helium abundances, and the form of the relationships among these properties. We find that N/O stays relatively constant at about 0.2 from the lowest core mass up to about 0.65 M, whereupon it climbs very suddenly to high levels, between 1 and 2, by 0.7 M. Above 0.9 M, N/O either stays constant with increasing core mass or even declines, but it does not continue to increase. The relation is similar to that seen for the Galaxy by Kaler, Shaw, and Kwitter, but is r much tighter since the distances to planetaries in the Clouds are much better known. We also see a continuous increase of He/H with core mass for masses below 0.8 M. The almost discontinuous increase of N/O, which appears correlated with a drop in C/O, cannot be explained by ordinary dredge-up processes but can be understood by invoking envelope-burning. Our results provide powerful input for improvement of stellar theories and for the understanding of chemical enrichment in the envelopes of giants and in galaxies.

Original languageEnglish (US)
Pages (from-to)491-502
Number of pages12
JournalAstrophysical Journal
Issue number2
StatePublished - Oct 20 1990


  • Galaxies: Magellanic Clouds
  • Nebulae: abundances
  • Nebulae: planetary
  • Stars: evolution

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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