The R-process alliance: analysis of limited-r stars

Context. In recent years, the R-Process Alliance (RPA) has conducted a successful search for stars that are enhanced in elements produced by the rapid neutron-capture (r-)process. In particular, the RPA has uncovered a number of stars that are strongly enriched in light r-process elements, such as S...

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Main Authors: Xylakis-Dornbusch, Theodora (Author) , Hansen, T. T. (Author) , Beers, T. C. (Author) , Christlieb, Norbert (Author) , Ezzeddine, R. (Author) , Frebel, A. (Author) , Holmbeck, E. (Author) , Placco, V. M. (Author) , Roederer, I. U. (Author) , Sakari, C. M. (Author) , Sneden, C. (Author)
Format: Article (Journal)
Language:English
Published: August 2024
In: Astronomy and astrophysics
Year: 2024, Volume: 688, Pages: 1-13
ISSN:1432-0746
DOI:10.1051/0004-6361/202449376
Online Access:Verlag, kostenfrei, Volltext: https://doi.org/10.1051/0004-6361/202449376
Verlag, kostenfrei, Volltext: https://www.aanda.org/articles/aa/abs/2024/08/aa49376-24/aa49376-24.html
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Author Notes:T. Xylakis-Dornbusch, T.T. Hansen, T.C. Beers, N. Christlieb, R. Ezzeddine, A. Frebel, E. Holmbeck, V.M. Placco, I.U. Roederer, C.M. Sakari, and C. Sneden
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Summary:Context. In recent years, the R-Process Alliance (RPA) has conducted a successful search for stars that are enhanced in elements produced by the rapid neutron-capture (r-)process. In particular, the RPA has uncovered a number of stars that are strongly enriched in light r-process elements, such as Sr, Y, and Zr. These so-called limited-r stars were investigated to explore the astrophysical production site(s) of these elements. Aims. We investigate the possible formation sites for light neutron-capture elements by deriving detailed abundances for neutron-capture elements from high-resolution spectra with a high signal-to-noise ratio of three limited-r stars. Methods. We conducted a kinematic analysis and a 1D local thermodynamic equilibrium spectroscopic abundance analysis of three stars. Furthermore, we calculated the lanthanide mass fraction (XLa) of our stars and of limited-r stars from the literature. Results. We found that the abundance pattern of neutron-capture elements of limited-r stars behaves differently depending on their [Ba/Eu] ratios, and we suggest that this should be taken into account in future investigations of their abundances. Furthermore, we found that the XLa of limited-r stars is lower than that of the kilonova AT2017gfo. The latter seems to be in the transition zone between limited-rXLa and that of r-I and r-II stars. Finally, we found that unlike r-I and r-II stars, the current sample of limited-r stars is largely born in the Galaxy and is not accreted.
Item Description:Online veröffentlicht: 13. August 2024
Gesehen am 07.11.2024
Physical Description:Online Resource
ISSN:1432-0746
DOI:10.1051/0004-6361/202449376