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

Peloso, E. F. del; Cunha, Kátia; Silva, L. da; Mello, G. F. Porto de

doi:10.1051/0004-6361:20053077

Cited by 31 publications

(23 citation statements)

References 23 publications

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“…Intrinsic cosmic scatter can be the result of the heterogenous nature of the original interstellar medium from which each star was formed. However, all too often scatter arises from differences in the procedure used by different authors, which could involve parameters as divers as different line sets, atomic constants, h f s employed (del Peloso et al 2005), solar abundances as reference, atmosphere models, and spectrum synthesis codes. Table 6 shows that the difference between results obtained for Mn abundances by different authors for some stars can reach 0.50 dex, whereas for Cu and Zn this difference is smaller.…”

Section: Abundance Scattermentioning

confidence: 99%

Mn, Cu, and Zn abundances in barium stars and their correlations with neutron capture elements

Allen

Mello

2010

A&A

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Barium stars are optimal sites for studying the correlations between the neutron-capture elements and other species that may be depleted or enhanced, because they act as neutron seeds or poisons during the operation of the s-process. These data are necessary to help constrain the modeling of the neutron-capture paths and explain the s-process abundance curve of the solar system. Chemical abundances for a large number of barium stars with different degrees of s-process excesses, masses, metallicities, and evolutionary states are a crucial step towards this goal. We present abundances of Mn, Cu, Zn, and various light and heavy elements for a sample of barium and normal giant stars, and present correlations between abundances contributed to different degrees by the weak-s, mains, and r-processes of neutron capture, between Fe-peak elements and heavy elements. Data from the literature are also considered in order to better study the abundance pattern of peculiar stars. The stellar spectra were observed with FEROS/ESO. The stellar atmospheric parameters of the eight barium giant stars and six normal giants that we analyzed lie in the range 4300 < T eff /K < 5300, −0.7 < [Fe/H] ≤ 0.12 and 1.5 ≤ log g < 2.9. Carbon and nitrogen abundances were derived by spectral synthesis of the molecular bands of C 2 , CH, and CN. For all other elements we used the atomic lines to perform the spectral synthesis. A very large scatter was found mainly for the Mn abundances when data from the literature were considered. We found that [Zn/Fe] correlates well with the heavy element excesses, its abundance clearly increasing as the heavy element excesses increase, a trend not shown by the [Cu/Fe] and [Mn/Fe] ratios. Also, the ratios involving Mn, Cu, and Zn and heavy elements usually show an increasing trend toward higher metallicities. Our results suggest that a larger fraction of the Zn synthesis than of Cu is owed to massive stars, and that the contribution of the main-s process to the synthesis of both elements is small. We also conclude that Mn is mostly synthesized by SN Ia, and that a non-negligible fraction of the synthesis of Mn, Cu, and Zn is owed to the weak s-process.

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Section: Abundance Scattermentioning

confidence: 99%

Mn, Cu, and Zn abundances in barium stars and their correlations with neutron capture elements

Allen

Mello

2010

A&A

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“…All fine-structure and hyperfine-structure components for the lines of Cu i, Mn i and Eu ii were explicitly included. The g f -values for Cu i are from Koch & Richter (1968), those for Mn i and Eu ii are from del Peloso et al (2005).…”

Section: Abundance Analysismentioning

confidence: 99%

High-resolution spectroscopic observations of two chemically peculiar metal-poor stars: HD 10613 and BD+04°2466

Pereira

Драке²

2009

A&A

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Aims. We determined the atmospheric parameters and abundance pattern of two chemically peculiar metal-poor stars: HD 10613 and BD+04 • 2466 in order to better understand their evolutionary state and the nature of the s-element enhancement of these stars. Methods. We used high resolution optical spectroscopy. Atmospheric parameters and abundances were determined in the localthermodynamic-equilibrium model atmospheres of Kurucz using the spectral analysis code MOOG. • 2466 the abundance of lead is in agreement with predictions from AGB models. Due to the low luminosity of these two stars, their observed s-process overabundance is better explained by mass-transfer in the past from an AGB star.

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“…In the framework of testing nucleosynthesis models, Ellison et al (2001) identified Co as a rewarding element to study galactic and stellar formation histories through the observed abundance trends (del Peloso et al 2005). For example, the agreement of the modeled time-dependent ejecta compositions and velocities with observed Type 1a supernovae spectra requires a substantial initial presence of Ni , Co , and Fe in the outer layers of the ejecta (Hillebrandt & Niemeyer 2000).…”

Section: Introductionmentioning

confidence: 99%

Dielectronic recombination of argon-like ions

Nikolić¹,

Gorczyca²,

Korista³

et al. 2010

A&A

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Context. We present a theoretical investigation of dielectronic recombination (DR) of Ar-like ions that sheds new light on the behavior of the rate coefficient at low-temperatures where these ions form in photoionized plasmas.Aims. We provide results for the total and partial Maxwellian-averaged DR rate coefficients from the initial ground level of K iiZn xiii ions. It is expected that these new results will advance the accuracy of the ionization balance for Ar-like M-shell ions and pave the way towards a detailed modeling of astrophysically relevant X-ray absorption features. Methods. We utilize the AUTOSTRUCTURE computer code to obtain the accurate core-excitation thresholds in target ions and carry out multiconfiguration Breit-Pauli (MCBP) calculations of the DR cross section in the independent-processes, isolated-resonance, distorted-wave (IPIRDW) approximation. Results. Our results mediate the complete absence of direct DR calculations for certain Ar-like ions and question the reliability of the existing empirical rate formulas, often inferred from renormalized data within this isoelectronic sequence.

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

Cited by 31 publications

References 23 publications

Mn, Cu, and Zn abundances in barium stars and their correlations with neutron capture elements

Mn, Cu, and Zn abundances in barium stars and their correlations with neutron capture elements

High-resolution spectroscopic observations of two chemically peculiar metal-poor stars: HD 10613 and BD+04°2466

Dielectronic recombination of argon-like ions

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