Exploring circumstellar effects on the Li abundances in massive Galactic AGB stars

V. Pérez-Mesa, O. Zamora, D. A. García-Hernández, B. Plez, A. Manchado, A. I. Karakas, M. Lugaro

Research output: Chapter in Book/Report/Conference proceedingConference PaperOther


We have explored the circumstellar effects on the Li abundance determination in a complete sample of O-rich Galactic asymptotic giant branch (AGB) stars, previously studied with hydrostatic models. We use a modified version of the spectral synthesis code Turbospectrum and more realistic extended model atmospheres that consider the presence of a gaseous circumstellar envelope and a radial wind in these massive AGB stars. The Li abundances are determined from the 6708 Å Li I resonance line. The Li pseudo-dynamical abundances obtained are practically identical to those derived with hydrostatic models (a maximum difference of 0.3 dex is found in the only super Li-rich AGB star in our sample). The low Li abundance and therefore negligible Li I column-density in the circumstellar envelope likely explains the small differences between extended and hydrostatic models. Our results confirm the activation of the hot bottom burning (HBB) process in massive Galactic AGB stars.

Original languageEnglish
Title of host publicationMemorie della Societa Astronomica Italiana - Journal of the Italian Astronomical Society
Subtitle of host publication2017 AGB-Supernovae Mass Transition; Monte Porzio Catone; Italy; 27 March 2017 through 31 March 2017
EditorsA Karakas, P Ventura, F Dell'Agli, M Di Criscienzo
Place of PublicationItaly
Number of pages4
Publication statusPublished - 2017
EventThe AGB-Supernovae Mass Transition 2017 - Observatory of Rome, Monte Porzio Catone, Italy
Duration: 27 Mar 201731 Mar 2017

Publication series

NameMemorie della Società Astronomica Italiana
PublisherSocietà Astronomica Italiana
ISSN (Print)0037-8720


ConferenceThe AGB-Supernovae Mass Transition 2017
CityMonte Porzio Catone
OtherLittle is known about stars in the mass range between those that end their lives as white dwarfs and those that die in spectacular supernova explosions. The uncertainty stems from the fact that stars in this transition mass range from about ~7 to 11 solar masses are both difficult to model theoretically and there are few observational clues as to their evolutionary history. Following the ignition of carbon in the core under conditions of partial degeneracy, the stars then continue to evolve through the asymptotic giant branch (AGB) phase and are known as super-AGB stars. Super-AGB stars have oxygen-neon degenerate cores as opposed to the carbon-oxygen cores of their lower mass counterparts. The final fate of single super-AGB stars depends on the rate of mass loss from the surface: if the core can grow big enough to reach the Chandrasekhar mass then it will explode as an electron capture supernova.
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  • Nuclear reactions, nucleosynthesis, abundances
  • Stars: abundances
  • Stars: AGB and post-AGB
  • Stars: atmospheres
  • Stars: evolution
  • Stars: late-type

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