The r-process Alliance: spectroscopic follow-up of low-metallicity star candidates from the best & brightest survey

Resumo

We present results from an observing campaign to identify low-metallicity stars in the Best & Brightest Survey. From medium-resolution (R ∼ 1200–2000) spectroscopy of 857 candidates, we estimate the stellar atmospheric parameters (Teff, log g, and Fe H [ ]), as well as carbon and α-element abundances. We find that 69% of the observed stars have Fe H [ ] −1.0, 39% have Fe H [ ] −2.0, and 2% have Fe H [ ] −3.0. There are also 133 carbon-enhanced metal-poor (CEMP) stars in this sample, with 97 CEMP Group I and 36 CEMP Group II stars identified in the A(C) versus [Fe/H] diagram. A subset of the confirmed low-metallicity stars were followed-up with high-resolution spectroscopy, as part of the R-process Alliance, with the goal of identifying new highly and moderately r-process-enhanced stars. Comparison between the stellar atmospheric parameters estimated in this work and from high-resolution spectroscopy exhibit good agreement, confirming our expectation that medium-resolution observing campaigns are an effective way of selecting interesting stars for further, more targeted, efforts.

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Citação

PLACCO, Vinicius M. et al. The r-process Alliance: spectroscopic follow-up of low-metallicity star candidates from the best & brightest survey. The Astrophysical Journal, Bristol, v. 870, n. 2, e122, 2019. DOI: 10.3847/1538-4357/aaf3b9. Disponível em: https://iopscience.iop.org/article/10.3847/1538-4357/aaf3b9. Acesso em: 11 maio 2023.