Galactic planetary nebulae with precise nebular abundances as a tool to understand the evolution of asymptotic giant branch stars. Issue 1 (7th June 2016)

• Record Type: Journal Article
• Authors: García-Hernández, D. A.; Ventura, P.; Delgado-Inglada, G.; Dell'Agli, F.; Di Criscienzo, M.; Yagüe, A.
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 461:Issue 1(2016)
• Page Start: 542
• Page End: 551
• Publication Date: 2016-06-07
• Subjects: nuclear reactions, nucleosynthesis, abundances -- stars: abundances -- stars: AGB and post-AGB -- planetary nebulae: general -- Galaxy: abundances; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stw1349
• Languages: English
• ISSNs: 0035-8711

Abstract

Abstract: We present nucleosynthesis predictions (HeCNOCl) from asymptotic giant branch (AGB) models, with diffusive overshooting from all the convective borders, in the metallicity range Z⊙ /4 < Z < 2 Z⊙ . They are compared to recent precise nebular abundances in a sample of Galactic planetary nebulae (PNe) that is divided among double-dust chemistry (DC) and oxygen-dust chemistry (OC) according to the infrared dust features. Unlike the similar subsample of Galactic carbon-dust chemistry PNe recently analysed by us, here the individual abundance errors, the higher metallicity spread, and the uncertain dust types/subtypes in some PNe do not allow a clear determination of the AGB progenitor masses (and formation epochs) for both PNe samples; the comparison is thus more focused on a object-by-object basis. The lowest metallicity OC PNe evolve from low-mass (∼1 M⊙ ) O-rich AGBs, while the higher metallicity ones (all with uncertain dust classifications) display a chemical pattern similar to the DC PNe. In agreement with recent literature, the DC PNe mostly descend from high-mass ( M ≥ 3.5 M⊙ ) solar/supersolar metallicity AGBs that experience hot bottom burning (HBB), but other formation channels in low-mass AGBs like extra mixing, stellar rotation, binary interaction, or He pre-enrichment cannot be disregarded until more accurate C/O ratios would be obtained. Two objects among the DC PNe show the imprint of advanced CNO processing and deep second dredge-up, suggesting progenitors masses close to the limit to evolve as core collapse supernovae (above 6 M ⊙ ). Their actual C/O ratio, if confirmed, indicate contamination from the third dredge-up, rejecting the hypothesis that the chemical composition of such high-metallicity massive AGBs is modified exclusively by HBB.