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  • The R-process Alliance: Fifth Data Release from the Search for R-process-enhanced Metal-poor Stars in the Galactic Halo with the GTC*
Title: The R-process Alliance: Fifth Data Release from the Search for R-process-enhanced Metal-poor Stars in the Galactic Halo with the GTC*
Abstract Understanding the abundance pattern of metal-poor stars and the production of heavy elements through various nucleosynthesis processes offers crucial insights into the chemical evolution of the Milky Way, revealing primary sites and major sources of rapid neutron-capture process (r-process) material in the Universe. In this fifth data release from theR-Process Alliance (RPA), we present the detailed chemical abundances of 41 faint (down toV= 15.8) and extremely metal-poor (down to [Fe/H] = −3.3) halo stars selected from the RPA. We obtained high-resolution spectra for these objects with the HORuS spectrograph on the Gran Telescopio Canarias. We measure the abundances of light,α, Fe-peak, and neutron-capture elements. We report the discovery of five carbon-enhanced metal-poor, one limited-r, threer-I, and fourr-II stars, and six Mg-poor stars. We also identify one star of a possible globular cluster origin at an extremely low metallicity at [Fe/H] = −3.0. This adds to the growing evidence of a lower-limit metallicity floor for globular cluster abundances. We use the abundances of Fe-peak elements and theα-elements to investigate the contributions from different nucleosynthesis channels in the progenitor supernovae. We find the distribution of [Mg/Eu] as a function of [Fe/H] to have different enrichment levels, indicating different possible pathways and sites of their production. We also reveal differences in the trends of the neutron-capture element abundances of Sr, Ba, and Eu of variousr-I andr-II stars from the RPA data releases, which provide constraints on their nucleosynthesis sites and subsequent evolution.  more » « less
Award ID(s):
2307436 1927130 2206263
PAR ID:
10637299
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ;
Publisher / Repository:
Astrophysical Journal Supplements
Date Published:
Journal Name:
The Astrophysical Journal Supplement Series
Volume:
274
Issue:
2
ISSN:
0067-0049
Page Range / eLocation ID:
39
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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