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The Hamburg/ESO R-p...
The Hamburg/ESO R-process enhanced star survey (HERES) IV. Detailed abundance analysis and age dating of the strongly r-process enhanced stars CS 29491-069 and HE 1219-0312
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Hayek, W (författare)
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Wiesendahl, U (författare)
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Christlieb, N (författare)
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- Eriksson, K (författare)
- Uppsala universitet,Institutionen för fysik och astronomi
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- Korn, A. J. (författare)
- Uppsala universitet,Institutionen för fysik och astronomi
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- Barklem, P. S. (författare)
- Uppsala universitet,Institutionen för fysik och astronomi
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Hill, V (författare)
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Beers, C (författare)
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Farouqi, K (författare)
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Pfeiffer, B (författare)
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Kratz, K.-L. (författare)
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(creator_code:org_t)
- 2009-07-02
- 2009
- Engelska.
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 504:2, s. 511-524
- Relaterad länk:
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https://www.aanda.or...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- We report on a detailed abundance analysis of two strongly r-process enhanced, very metal-poor stars newly discovered in the HERES project, CS 29491-069 ([Fe/H] = -2.51, [r/Fe] = +1.1) and HE 1219-0312 ([Fe/H] = -2.96, [r/Fe] = +1.5). The analysis is based on high-quality VLT/UVES spectra and MARCS model atmospheres. We detect lines of 15 heavy elements in the spectrum of CS 29491-069, and 18 in HE 1219-0312; in both cases including the Th II 4019 angstrom line. The heavy-element abundance patterns of these two stars are mostly well-matched to scaled solar residual abundances not formed by the s-process. We also compare the observed pattern with recent high-entropy wind (HEW) calculations, which assume core-collapse supernovae of massive stars as the astrophysical environment for the r-process, and find good agreement for most lanthanides. The abundance ratios of the lighter elements strontium, yttrium, and zirconium, which are presumably not formed by the main r-process, are reproduced well by the model. Radioactive dating for CS 29491-069 with the observed thorium and rare-earth element abundance pairs results in an average age of 9.5 Gyr, when based on solar r-process residuals, and 17.6 Gyr, when using HEW model predictions. Chronometry seems to fail in the case of HE 1219-0312, resulting in a negative age due to its high thorium abundance. HE 1219-0312 could therefore exhibit an overabundance of the heaviest elements, which is sometimes called an "actinide boost".
Ämnesord
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
Nyckelord
- stars: abundances
- nuclear reactions
- nucleosynthesis
- abundances
- Galaxy: halo
- Galaxy: abundances
- Galaxy: evolution
- Physics
- Fysik
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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Till lärosätets databas
- Av författaren/redakt...
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Hayek, W
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Wiesendahl, U
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Christlieb, N
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Eriksson, K
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Korn, A. J.
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Barklem, P. S.
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visa fler...
-
Hill, V
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Beers, C
-
Farouqi, K
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Pfeiffer, B
-
Kratz, K.-L.
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visa färre...
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- NATURVETENSKAP
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NATURVETENSKAP
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och Fysik
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Astronomy and As ...
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Uppsala universitet