Issue |
A&A
Volume 441, Number 3, October III 2005
|
|
---|---|---|
Page(s) | 1149 - 1156 | |
Section | Stellar atmospheres | |
DOI | https://doi.org/10.1051/0004-6361:20053077 | |
Published online | 23 September 2005 |
Abundances of Mn, Co and Eu in a sample of 20 F–G disk stars: the influence of hyperfine structure splitting
1
Observatório Nacional/MCT, Rua General José Cristino 77, 20921-400 Rio de Janeiro, RJ, Brazil e-mail: [epeloso;katia;licio]@on.br
2
Observatório do Valongo/UFRJ, Ladeira do Pedro Antônio 43, 20080-090 Rio de Janeiro, RJ, Brazil e-mail: gustavo@ov.ufrj.br
Received:
16
March
2005
Accepted:
22
June
2005
We present Mn, Co and Eu abundances for a sample of 20
disk F and G dwarfs and subgiants with metallicities in the range
. 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
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 Ia 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
in the range
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.
Key words: stars: abundances / atomic data
© ESO, 2005
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