Bibcode
García-Hernández, D. A.; Ventura, P.; Delgado-Inglada, G.; Dell'Agli, F.; Di Criscienzo, M.; Yagüe, A.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 461, Issue 1, p.542-551
Advertised on:
9
2016
Citations
17
Refereed citations
13
Description
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 6M⊙).
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.