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arXiv · 1602.05346

Probing O-enrichment in C-rich dust planetary nebulae

D. A. Garcia-Hernandez·P. Ventura·G. Delgado-Inglada·F. Dell'Agli·M. Di Criscienzo·A. Yagüe
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Abstract

The abundance of O in planetary nebulae (PNe) has been historically used as a metallicity indicator of the interstellar medium (ISM) where they originated; e.g., it has been widely used to study metallicity gradients in our Galaxy and beyond. However, clear observational evidence for O self enrichment in low-metallicity Galactic PNe with C-rich dust has been recently reported. Here we report asymptotic giant branch (AGB) nucleosynthesis predictions for the abundances of the CNO elements and helium in the metallicity range Zsun/4 < Z < 2Zsun. Our AGB models, with diffusive overshooting from all the convective borders, predict that O is overproduced in low-Z low-mass (~1-3 Msun) AGB stars and nicely reproduce the recent O overabundances observed in C-rich dust PNe. This confirms that O is not always a good proxy of the original ISM metallicity and another chemical elements such as Cl or Ar should be used instead. The production of oxygen by low-mass stars should be thus considered in galactic-evolution models.

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D. A. Garcia-Hernandez, P. Ventura, G. Delgado-Inglada, F. Dell'Agli, M. Di Criscienzo, A. Yagüe. 2016-02-17. Probing O-enrichment in C-rich dust planetary nebulae. https://doi.org/10.1093/mnrasl/slw029

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