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| Paper: |
Rubidium-rich Asymptotic Giant Branch Stars in the Magellanic
Clouds |
| Volume: |
445, Why Galaxies Care about AGB Stars II: Shining Examples and Common Inhabitants |
| Page: |
437 |
| Authors: |
García-Hernández, D. A. |
| Abstract: |
The Magellanic Clouds (MCs) offer a unique opportunity to study the
stellar evolution and nucleosynthesis of massive Asymptotic Giant
Branch (AGB) stars in low metallicity environments where distances
are known. Rubidium is a key element to distinguish between high mass
AGB stars and low mass AGB stars or other types of astronomical
objects such as massive red supergiant stars.
Theoretically, high mass AGB stars are predicted to produce a lot of
Rb. We present the discovery of massive Rb-rich AGB stars in the MCs,
confirming for the first time that these stars also exist in other
galaxies. Our findings show that these stars are generally brighter
than the standard adopted luminosity limit
(Mbol ≈ –7.1)
for AGB stars. The observations of massive MC AGBs are qualitatively
predicted by the present theoretical models. However, these theoretical
models are far from matching the extremely high Rb overabundances
observed. This might be related to an incomplete present understanding
of the atmospheres of these stars. |
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