Galactic Cosmochronometry from Radioactive Elements in the Spectra of Very Old Metal-Poor Stars
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چکیده
منابع مشابه
Galactic Cosmochronometry from Radioactive Elements in the Spectra of Very Old Metal-poor Stars
In a short review of neutron-capture elemental abundances in Galactic halo stars, emphasis is placed on the use of these elements to estimate the age of the Galactic halo. Two prominent characteristics of neutron-capture elements in halo stars are their large star-to-star scatter in the overall abundance level with respect to lighter elements, and the dominance of r-process abundance patterns a...
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We study the age and metallicity distribution function (MDF) of metal-poor stars in the Milky Way halo as a function of galactocentric radius by combining N-body simulations and semi-analytical methods. We find that the oldest stars populate the innermost region, while extremely metal-poor stars are more concentrated within r < 60 kpc. We predict that the MDF of [Fe/H]≤ −2 stars varies only ver...
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We have obtained high-resolution high signal-to-noise spectra of the S i nearinfrared doublet at 8694 Å in eight metal-poor stars with metallicities in the range −0.6 ≤[Fe/H]≤ −3.0. Elemental sulphur abundances were derived for six targets and upper limits were set for two of the most metal-poor stars in the sample. The sulphur doublet at 8694.62 Å has been detected in three stars (HD19445, HD2...
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Metal-poor stars provide information on the characteristics and chemical evolution of the halo population of the Galaxy, the first epoch of star formation and Galaxy formation (not just locally but with relevance to high-redshift objects), and big bang nucleosynthesis. This review looks at recent developments in this subject.
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We have observed the B I λ 2497 Å line to derive the boron abundances of two very metal-poor stars selected to help in tracing the origin and evolution of this element in the early Galaxy: BD +23◦3130 and HD 84937. The observations were conducted using the Goddard High Resolution Spectrograph on board the Hubble Space Telescope. A very detailed abundance analysis via spectral synthesis has been...
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ژورنال
عنوان ژورنال: Physica Scripta
سال: 2002
ISSN: 0031-8949
DOI: 10.1238/physica.topical.100a00015