منابع مشابه
Three - micron spectra of AGB stars and supergiants in nearby galaxies ⋆
The dependence of stellar molecular bands on the metallicity is studied using infrared L-band spectra of AGB stars (both carbon-rich and oxygen-rich) and M-type supergiants in the Large and Small Magellanic Clouds (LMC and SMC) and in the Sagittarius Dwarf Spheroidal Galaxy. The spectra cover SiO bands for oxygen-rich stars, and acetylene (C 2 H 2), CH and HCN bands for carbon-rich AGB stars. T...
متن کاملPost-AGB stars as testbeds of nucleosynthesis in AGB stars
We construct a data base of 125 post-AGB objects (including R CrB and extreme helium stars) with published photospheric parameters (effective temperature and gravity) and chemical composition. We estimate the masses of the postAGB stars by comparing their position in the (log Teff , log g) plane with theoretical evolutionary tracks of different masses. We construct various diagrams, with the ai...
متن کاملDust from AGB stars
Dust is formed in the expanding atmosphere during late stages of stellar evolution. Dust influences the dynamics and thermodynamics of the stellar atmosphere by its opacity. The dust opacity depends both on the optical properties of the grain material as well as on the amount of dust present. A rich source of information on some mineral phases of dust in AGB stars comes from the study of presol...
متن کاملMass-loss rates and luminosity functions of dust-enshrouded AGB stars and red supergiants in the LMC
A radiative transfer code is used to model the spectral energy distributions of 57 mass-losing Asymptotic Giant Branch (AGB) stars and red supergiants (RSGs) in the Large Magellanic Cloud (LMC) for which ISO spectroscopic and photometric data are available. As a result we derive mass-loss rates and bolometric luminosities. A gap in the luminosity distribution around Mbol = −7.5 mag separates AG...
متن کاملAGB Stars: Summary and Warning
We review the evolution and nucleosynthesis of AGB stars. We then discuss some of the contentious issues and quantitative uncertainties in current models.
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1993
ISSN: 0074-1809
DOI: 10.1017/s0074180900171086