New f-values in C I and the CNO abundances in the sun

Biémont, Émile; Hibbert, A; Godefroid, Michel; Vaeck, Nathalie

doi:10.1086/172932

Cited by 39 publications

(86 citation statements)

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“…For the nitrogen, the EW measurements differ also between different works. Comparing the measurements of the EWs of two authoritative works such as Grevesse et al (1990) and Biémont et al (1990), we conclude that there is good agreement for our selected lines of nitrogen. The authors measure similar values without any systematic differences being evident.…”

Section: Comparison Of Different Ew Measurementssupporting

confidence: 54%

“…In our analysis, we used the EWs of Grevesse et al (1990) and Biémont et al (1990), which are in excellent agreement. For a few selected lines, we derived in addition the nitrogen abundance from detailed line profile fitting (see Fig.…”

Section: Data Used In This Studymentioning

confidence: 91%

“…However, line fitting with 3D spectra can become a tedious task, and we therefore prefer to rely on equivalent width measurements. We believe that we cannot achieve superior measurement of the EWs than the careful works by Grevesse et al (1990) and Biémont et al (1990). In principle, we could also measure the EWs in data from the other atlases, but our above line fitting exercise implies that this would introduce an additional scatter of the order of at most approximately 0.03 dex, due to the differences between atlases.…”

Section: Line-profile Fittingmentioning

confidence: 93%

“…We consider the variation in the NLTE corrections of the various components, relative to the result of the 3D model, as an indication of the uncertainty associated with the 1D approximation. Grevesse et al (1990), with B are from Biémont et al (1990). Column (1) is the wavelength; Cols.…”

Section: Influence Of Horizontal Temperature Fluctuationsmentioning

confidence: 99%

“…We determined individual LTE nitrogen abundances, A(N) LTE using the 3D, 3D , 1D LHD , and HM model, respectively, and the equivalent width measurements by Grevesse et al (1990) and Biémont et al (1990) where available. The results are given in Table 2.…”

Section: Lte Abundance From Selected Linesmentioning

confidence: 99%

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The solar photospheric nitrogen abundance

Caffau¹,

Maiorca

Bonifacio

et al. 2009

A&A

136

128

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Context. In recent years, the solar chemical abundances have been studied in considerable detail because of discrepant values of solar metallicity inferred from different indicators, i.e., on the one hand, the "sub-solar" photospheric abundances resulting from spectroscopic chemical composition analyses with the aid of 3D hydrodynamical models of the solar atmosphere, and, on the other hand, the high metallicity inferred by helioseismology. Aims. After investigating the solar oxygen abundance using a CO 5 BOLD 3D hydrodynamical solar model in previous work, we undertake a similar approach studying the solar abundance of nitrogen, since this element accounts for a significant fraction of the overall solar metallicity, Z. Methods. We used a selection of atomic spectral lines to determine the solar nitrogen abundance, relying mainly on equivalent width measurements in the literature. We investigate the influence on the abundance analysis, of both deviations from local thermodynamic equilibrium ("NLTE effects") and photospheric inhomogeneities ("granulation effects"). Results. We recommend use of a solar nitrogen abundance of A(N) = 7.86 ± 0.12 , whose error bar reflects the line-to-line scatter. Conclusions. The solar metallicity implied by the CO 5 BOLD-based nitrogen and oxygen abundances is in the range 0.0145 ≤ Z ≤ 0.0167. This result is a step towards reconciling photospheric abundances with helioseismic constraints on Z. Our most suitable estimates are Z = 0.0156 and Z/X = 0.0213.

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Section: Comparison Of Different Ew Measurementssupporting

confidence: 54%

Section: Data Used In This Studymentioning

confidence: 91%

Section: Line-profile Fittingmentioning

confidence: 93%

Section: Influence Of Horizontal Temperature Fluctuationsmentioning

confidence: 99%

Section: Lte Abundance From Selected Linesmentioning

confidence: 99%

See 3 more Smart Citations

The solar photospheric nitrogen abundance

Caffau¹,

Maiorca

Bonifacio

et al. 2009

A&A

136

128

View full text Add to dashboard Cite

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Astronomy and Astrophysics

Susalla¹

2015

A Companion to the History of American Science

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Remarkable inconsistencies between elemental abundances in the main sequence stars and their progeny F-G supergiants are discussed. Comparative abundance analysis of the hot main sequence stars, the cepheid U Sgr and two cool supergiants belonging to young open cluster M 25 is performed. The detected disaccord in the abundances of carbon, oxygen and other elements between these stars having a common origin but occupying at present different evolutionary stages may be due to the fact that the chemical anomalies observed in B stars are caused by the mechanism of the radiative diffusion in the upper atmosphere layers. The chemical composition of B stars determined spectroscopically may not reflect correctly their true chemical composition, nor the chemical composition of the interstellar medium. On the other hand such abundance anomalies are not expected for F-G supergiants which have suffered the large scale mixing in the red giant phase. The observed abundances for these objects are much more reliable as a reference point in the study of galactic chemical evolution.Three new Be stars are discovered in M 25. Our study has doubled the number of Be stars known in this cluster.

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Solar Chemical Abundances Determined with a CO5BOLD 3D Model Atmosphere

et al. 2010

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In the last decade, the photospheric solar metallicity as determined from spectroscopy experienced a remarkable downward revision. Part of this effect can be attributed to an improvement of atomic data and the inclusion of NLTE computations, but also the use of hydrodynamical model atmospheres seemed to play a role. This "decrease" with time of the metallicity of the solar photosphere increased the disagreement with the results from helioseismology. With a CO 5 BOLD 3D model of the solar atmosphere, the CIFIST team at the Paris Observatory re-determined the photospheric solar abundances of several elements, among them C, N, and O. The spectroscopic abundances are obtained by fitting the equivalent width and/or the profile of observed spectral lines with synthetic spectra computed from the 3D model atmosphere. We conclude that the effects of granular fluctuations de- E. Caffau et al. pend on the characteristics of the individual lines, but are found to be relevant only in a few particular cases. 3D effects are not responsible for the systematic lowering of the solar abundances in recent years. The solar metallicity resulting from this analysis is Z = 0.0153, Z/X = 0.0209.

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New f-values in C I and the CNO abundances in the sun

Cited by 39 publications

References 0 publications

The solar photospheric nitrogen abundance

The solar photospheric nitrogen abundance

Astronomy and Astrophysics

Solar Chemical Abundances Determined with a CO5BOLD 3D Model Atmosphere

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