Rb-RICH ASYMPTOTIC GIANT BRANCH STARS IN THE MAGELLANIC CLOUDS

@article{GarcaHernndez2009RbRICHAG,
  title={Rb-RICH ASYMPTOTIC GIANT BRANCH STARS IN THE MAGELLANIC CLOUDS},
  author={Domingo An{\'i}bal Garc{\'i}a-Hern{\'a}ndez and Arturo Manchado and David L. Lambert and Bertrand Plez and Pedro Garcı́a-Lario and Francesca D’Antona and Maria Lugaro and Amanda I. Karakas and Mark A. van Raai},
  journal={The Astrophysical Journal},
  year={2009},
  volume={705},
  pages={L31 - L35}
}
We present high-resolution (R ∼ 60,000) optical spectra of a carefully selected sample of heavily obscured and presumably massive O-rich asymptotic giant branch (AGB) stars in the Magellanic Clouds. We report the discovery of strong Rb i lines at 7800 Å in four Rb-rich LMC stars at luminosities equal to or greater than the standard adopted luminosity limit for AGB stars (Mbol ∼ −7.1), confirming that “hot bottom burning” may produce a flux excess in the more massive AGB stars. In the SMC sample… 

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References

SHOWING 1-10 OF 28 REFERENCES

Obscured asymptotic giant branch variables in the Large Magellanic Cloud and the period–luminosity relation

The characteristics of oxygen-rich and carbon-rich, large amplitude (�K > 0.4 mag), asymptotic giant branch variables in the Large Magellanic Clouds are discussed, with an emphasis on those obscured

New discoveries and challenges for the s process in AGB stars

Approximately half of the solar abundances of nuclei heavier than iron are created in the deep layers of asymptotic giant branch (AGB) stars via slow neutron captures (the s process). Freshly made

Lithium and zirconium abundances in massive Galactic O-rich AGB stars

Lithium and zirconium abundances (the latter taken as representative of s-process enrichment) are determined for a large sample of massive Galactic O-rich AGB stars, for which high-resolution optical

Stellar Models and Yields of Asymptotic Giant Branch Stars

Abstract We present stellar yields calculated from detailed models of low and intermediate-mass asymptotic giant branch (AGB) stars. We evolve models with a range of mass from 1 to 6 M⊙, and initial

Lithium abundances and other clues to envelope burning in small Magellanic Cloud asymptotic giant branch stars

We present a chemical analysis of seven luminous asymptotic giant branch stars and one M supergiant of the Small Magellanic Cloud. The abundances are derived from high-resolution spectra by spectrum

Rubidium-Rich Asymptotic Giant Branch Stars

A long-debated issue concerning the nucleosynthesis of neutron-rich elements in asymptotic giant branch (AGB) stars is the identification of the neutron source. We report intermediate-mass (4 to 8

Long-period variables in the Large Magellanic Cloud. II. Infrared photometry, spectral classification, AGB evolution, and spatial distribution

Infrared JHK photometry and visual spectra have been obtained for a large sample of long-period variables (LPVs) in the Large Magellanic Cloud (LMC). Various aspects of the asymptotic giant branch

The 85Kr s-Process Branching and the Mass of Carbon Stars

We present new spectroscopic observations for a sample of C(N)-type red giants. These objects belong to the class of asymptotic giant branch stars, experiencing thermal instabilities in the

Long-period variables in the Magellanic Clouds: Supergiants, AGB stars, supernova precursors, planetary nebula precursors, and enrichment of the interstellar medium

Infrared JHK magnitudes and low-dispersion red spectra have been obtained for 90 long-period variables (LPVs) in the Small and Large Magellanic Clouds. The LPVs fall into two distinct groups, core

Asymptotic giant branch superwind speed at low metallicity

ABSTRACT We present the results of a survey for OH maser emission at 1612 MHz from dust-enshrouded AGB stars and supergiants in the LMC and SMC, with the Parkes radiotelescope, aimed at deriving the