Rb and Zr abundances in massive Galactic AGB stars revisited

11th Pacific Rim Conference on Stellar Astrophysics: Physics and Chemistry of the Late Stages of Stellar Evolution

物理学;天文学

Pérez-Mesa, V.^1,2 ; Zamora, O.^1,2 ; García-Hernández, D.A.^1,2 ; Plez, B.^3 ; Manchado, A.^1,2,4 ; Karakas, A.I.^5 ; Lugaro, M.^6,7

Instituto de Astrofísíca de Canarias, La Laguna, Tenerife

38200, Spain^1

Departamento de Astrofísica, Universidad de la Laguna, La Laguna, Tenerife

38206, Spain^2

Laboratoire Univers et Particules de Montpellier, Université Montpellier2, CNRS, Montpellier

34095, France^3

Consejo Superior de Investigaciones Científicas, Madrid

28006, Spain^4

Research School of Astronomy and Astrophysics, Australian National University, Canberra

ACT

2611, Australia^5

Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Budapest

1121, Hungary^6

Monash Centre for Astrophysics, Monash University, VIC

3800, Australia^7

关键词: AGB stars;    Asymptotic giant branch stars;    Circumstellar envelopes;    Dynamical model;    Hydrostatic model;    Model atmosphere;    Radial winds;    Spectral synthesis;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/728/7/072003/pdf
DOI  :  10.1088/1742-6596/728/7/072003

学科分类：天文学(综合)

来源: IOP

【 摘 要 】

We report new abundances of Rb and Zr in a sample of massive Galactic asymptotic giant branch (AGB) stars that were previously studied with hydrostatic models by using more realistic dynamical model atmospheres. We use a modified version of the spectral synthesis code Turbospectrum, and consider the presence of a circumstellar envelope and a radial wind in the modelling of these Galactic AGB stars. The Rb and Zr are determined from the 7800 Å Rb I resonant line and the 6474 Å ZrO bandhead, respectively, and they are compared with the AGB nucleosynthesis theoretical predictions. The derived Rb abundances are much lower (∼1-2 dex) with the new dynamical models, while the Zr abundances, however, are closer to the hydrostatic values. The new model atmospheres can help to resolve the problem of the mismatch between the observations and the nucleosynthesis theoretical predictions of massive AGB stars.