منابع مشابه
Lithium abundances in halo dwarfs
The pioneering observations of Spite & Spite showed lithium abundances in halo dwarfs to be almost uniform, irrespective of metallicity and mass over a range of effective temperatures from ∼5600 K up to the main-sequence turnoff. They inferred that the observed abundance was “hardly altered” from that produced in the hot Big Bang. Subsequent efforts have endeavoured to determine how small or la...
متن کاملLithium abundances of halo dwarfs based on excitation temperature
Context. The discovery of the Spite plateau in the abundances of 7Li for metal-poor stars led to the determination of an observationally deduced primordial lithium abundance. However, after the success of the Wilkinson Microwave Anisotropy Probe (WMAP) in determining the baryon density, ΩBh, there was a discrepancy between observationally determined and theoretically determined abundances in th...
متن کاملLithium abundances of halo dwarfs based on excitation temperatures
Context. The plateau in the abundance of 7Li in metal-poor stars was initially interpreted as an observational indicator of the primordial lithium abundance. However, this observational value is in disagreement with that deduced from calculations of Big Bang nucleosynthesis (BBN), when using the Wilkinson microwave anisotropy probe (WMAP) baryon density measurements. One of the most important f...
متن کاملEuropium abundances in F and G disk dwarfs ⋆ ⋆ ⋆
Europium abundances for 74 F and G dwarf stars of the galactic disk have been determined from the 4129.7 Å Eu ii line. The stars were selected from the sample of Edvardsson et al. (1993) and [Eu/Fe] shows a smaller scatter and a slightly weaker trend with [Fe/H] than found by Woolf et al. (1995). The data of the two analyses are homogenized and merged. We also discuss the adopted effective temp...
متن کاملLithium abundances in main-sequence F stars and sub-giants
The application to main-sequence stars of the rotation-induced mixing theory in the presence of μ-gradients leads to partial mixing in the lithium destruction region, not visible in the atmosphere. The induced lithium depletion becomes visible in the sub-giant phase as soon as the convective zone deepens enough. This may explain why the observed “ lithium dilution ” is smoother and the final di...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1991
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/253.4.610