Bibcode
Ventura, P.; Stanghellini, L.; Dell'Agli, F.; García-Hernández, D. A.; Di Criscienzo, M.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 452, Issue 4, p.3679-3688
Advertised on:
10
2015
Citations
28
Refereed citations
22
Description
We used a new generation of asymptotic giant branch (AGB) stellar models
that include dust formation in the stellar winds to find the links
between evolutionary models and the observed properties of a homogeneous
sample of Large Magellanic Cloud (LMC) planetary nebulae (PNe).
Comparison between the evolutionary yields of elements such as CNO and
the corresponding observed chemical abundances is a powerful tool to
shed light on evolutionary processes such as hot bottom burning (HBB)
and third dredge-up (TDU). We found that the occurrence of HBB is needed
to interpret the nitrogen-enriched (log (N/H) + 12 > 8) PNe. In
particular, N-rich PNe with the lowest carbon content are nicely
reproduced by AGB models of mass M ≥ 6 M⊙, whose
surface chemistry reflects the pure effects of HBB. PNe with log (N/H) +
12 < 7.5 correspond to ejecta of stars that have not experienced HBB,
with initial mass below ˜3 M⊙. Some of these stars
show very large carbon abundances, owing to the many TDU episodes
experienced. We found from our LMC PN sample that there is a threshold
to the amount of carbon accumulated at AGB surfaces, log (C/H) + 12 <
9. Confirmation of this constraint would indicate that, after the C-star
stage is reached, AGBs experience only a few thermal pulses, which
suggests a rapid loss of the external mantle, probably owing to the
effects of radiation pressure on carbonaceous dust particles present in
the circumstellar envelope. The implications of these findings for AGB
evolution theories and the need to extend the PN sample currently
available are discussed.
Related projects
Nucleosynthesis and molecular processes in the late stages of Stellar Evolution
Low- to intermediate-mass (M < 8 solar masses, Ms) stars represent the majority of stars in the Cosmos. They finish their lives on the Asymptotic Giant Branch (AGB) - just before they form planetary nebulae (PNe) - where they experience complex nucleosynthetic and molecular processes. AGB stars are important contributors to the enrichment of the
Domingo Aníbal
García Hernández