Bibcode
García-Hernández, D. A.; Ventura, P.; Delgado-Inglada, G.; Dell'Agli, F.; Di Criscienzo, M.; Yagüe, A.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 461, Issue 1, p.542-551
Fecha de publicación:
9
2016
Número de citas
17
Número de citas referidas
13
Descripción
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.