High-resolution spectroscopic analysis of four new chemically peculiar stars
| Autor: | M P Roriz, C B Pereira, S Junqueira, M Lugaro, N A Drake, C Sneden |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Monthly Notices of the Royal Astronomical Society. 518:5414-5443 |
| ISSN: | 1365-2966 0035-8711 |
| DOI: | 10.1093/mnras/stac3378 |
| Popis: | We present detailed chemical compositions of four stars on the first-ascent red giant branch that are classified as chemically peculiar, but lack comprehensive analyses at high spectral resolution. For BD+03{\deg}2688, HE 0457-1805, HE 1255-2324, and HE 2207-1746, we derived metallicities [Fe/H] $=-1.21$, $-0.19$, $-0.31$, and $-0.55$, respectively, indicating a range in Galactic population membership. In addition to atmospheric parameters, we extracted elemental abundances for 28 elements, including the evolutionary-sensitive CNO group and $^{12}$C/$^{13}$C ratios. Novel results are also presented for the heavy elements tungsten and thallium. All four stars have very large enhancements of neutron-capture elements, with high [La/Eu] ratios indicating enrichments from the slow neutron capture ($s$-process). To interpret these abundances, all indicative of [$s$/Fe] $> 1.0$, we compared our results with data from literature, as well as with predictions from the Monash and FRUITY $s$-process nucleosynthesis models. BD+03{\deg}2688, HE 1255-2324, and HE 2207-1746 show C/O $>1$, while HE 0457-1805 has C/O $ Comment: 33 pages, 24 figures, accepted for publication in MNRAS |
| Databáze: | OpenAIRE |
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