Abundances of Mn, Co and Eu in a sample of 20 F-G disk stars: The influence of hyperfine structure splitting

E. F. Del Peloso, K. Cunha, L. Da Silva, G. F. Porto De Mello

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28 Scopus citations


We present Mn, Co and Eu abundances for a sample of 20 disk F and G dwarfs and subgiants with metallicities in the range -0.8 ≤ [Fe/H] ≤ +0.3. We investigate the influence of hyperfine structure (HFS) on the derived abundances of Mn and Co by using HFS data from different sources in the literature, as well as calculated HFS from interaction factors A and B. Eu abundances were obtained from spectral synthesis of one Eu II line that takes into account HFS from a series of recent laboratory measurements. For the lines analysed in this study, we find that for manganese, the differences between abundances obtained with different HFSs are no greater than 0.10 dex. Our cobalt abundances are even less sensitive to the choice of HFS than Mn, presenting a 0.07 dex maximum difference between determinations with different HFSs. However, the cobalt HFS data from different sources are significantly different. Our abundance results for Mn offer an independent confirmation of literature results, favouring type la supernovae as the main nucleosynthesis site of Mn production, in contrast to trends of Mn versus metallicity previously reported in the literature. For Co, we obtain [Co/Fe] ∼ 0.0 in the range -0.3 < [Fe/H] < +0.3 and [Co/Fe] rising to a level of +0.2 when [Fe/H] decreases from -0.3 to -0.8, in disagreement with recent results in the literature. The observed discrepancies may be attributed to the lack of HFS in the works we used for comparison. Our results for Eu are in accordance with low-mass type II supernovae being the main site of the r-process nucleosynthesis.

Original languageEnglish (US)
Pages (from-to)1149-1156
Number of pages8
JournalAstronomy and astrophysics
Issue number3
StatePublished - Oct 2005
Externally publishedYes


  • Atomic data
  • Stars: abundances

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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