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| Verfasst von: | François, Patrick [VerfasserIn]  |
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| | Caffau, Elisabetta [VerfasserIn] |
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| | Christlieb, Norbert [VerfasserIn] |
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| | Klessen, Ralf S. [VerfasserIn] |
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| | Koch-Hansen, Andreas [VerfasserIn] |
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| | Ludwig, Hans-Günter [VerfasserIn] |
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| Titel: | TOPoS |
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| Titelzusatz: | V. Abundance ratios in a sample of very metal-poor turn-off stars |
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| Verf.angabe: | P. François, E. Caffau, P. Bonifacio, M. Spite, F. Spite, R. Cayrel, N. Christlieb, A.J. Gallagher, R. Klessen, A. Koch, H.-G. Ludwig, L. Monaco, B. Plez, M. Steffen, and S. Zaggia |
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| E-Jahr: | 2018 |
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| Jahr: | 14 December 2018 |
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| Umfang: | 9 S. |
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| Fussnoten: | Gesehen am 16.10.2020 |
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| Titel Quelle: | Enthalten in: Astronomy and astrophysics |
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| Ort Quelle: | Les Ulis : EDP Sciences, 1969 |
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| Jahr Quelle: | 2018 |
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| Band/Heft Quelle: | 620(2018) Artikel-Nummer A187, 9 Seiten |
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| ISSN Quelle: | 1432-0746 |
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| Abstract: | Extremely metal-poor stars are keys to understand the early evolution of our Galaxy. The ESO large programme TOPoS has been tailored to analyse a new set of metal-poor turn-off stars, whereas most of the previously known extremely metal-poor stars are giant stars.<i>Aims.<i/> Sixty five turn-off stars (preselected from SDSS spectra) have been observed with the X-shooter spectrograph at the ESO VLT Unit Telescope 2, to derive accurate and detailed abundances of magnesium, silicon, calcium, iron, strontium and barium.<i>Methods.<i/> We analysed medium-resolution spectra (<i>R<i/> ≃ 10 000) obtained with the ESO X-shooter spectrograph and computed the abundances of several α and neutron-capture elements using standard one-dimensional local thermodynamic equilibrium (1D LTE) model atmospheres.<i>Results.<i/> Our results confirms the super-solar [Mg/Fe] and [Ca/Fe] ratios in metal-poor turn-off stars as observed in metal-poor giant stars. We found a significant spread of the [α/Fe] ratios with several stars showing subsolar [Ca/Fe] ratios. We could measure the abundance of strontium in 12 stars of the sample, leading to abundance ratios [Sr/Fe] around the Solar value. We detected barium in two stars of the sample. One of the stars (SDSS J114424−004658) shows both very high [Ba/Fe] and [Sr/Fe] abundance ratios (>1 dex). |
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| DOI: | doi:10.1051/0004-6361/201834375 |
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| URL: | Bitte beachten Sie: Dies ist ein Bibliographieeintrag. Ein Volltextzugriff für Mitglieder der Universität besteht hier nur, falls für die entsprechende Zeitschrift/den entsprechenden Sammelband ein Abonnement besteht oder es sich um einen OpenAccess-Titel handelt.
Volltext: http://dx.doi.org/10.1051/0004-6361/201834375 |
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| | DOI: https://doi.org/10.1051/0004-6361/201834375 |
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| Datenträger: | Online-Ressource |
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| Sprache: | eng |
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| K10plus-PPN: | 1586572636 |
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| Verknüpfungen: | → Zeitschrift |
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