On the Composition of the Sun's Atmosphere

Russell, Henry Norris

doi:10.1086/143197

Cited by 191 publications

(54 citation statements)

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“…A summary of solar abundance measurement methods is contained in a rapporteur paper by von Steiger et al (2001). Russell (1929) made the first quantitative analysis of the chemical composition of the solar atmosphere. Using eye estimates of the solar line radiances, he derived the abundances of 56 elements.…”

Section: Elemental Abundancesmentioning

confidence: 99%

Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

et al. 2007

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In Part I of this review, the concepts of solar vacuum-ultraviolet (VUV) observations were outlined together with a discussion of the space instrumentation used for the investigations. A section on spectroradiometry provided some quantitative results on the solar VUV radiation without considering any details of the solar phenomena leading to the radiation. Here, in Part II, we present solar VUV observations over the last decades and their interpretations in terms of the plasma processes and the parameters of the solar atmosphere, with emphasis on the spatial and thermal structures of the chromosphere, transition region and corona of the quiet Sun. In addition, observations of active regions, solar flares and prominences are included as well as of small-scale events. Special sections are devoted to the elemental composition of the solar atmosphere and theoretical considerations on the heating of the corona and the generation of the solar wind.

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Section: Elemental Abundancesmentioning

confidence: 99%

Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

et al. 2007

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“…Its precise value has been debated in the literature since the late 1920s (Russell 1929). Summaries of these debates can be found in Grevesse & Sauval (1998), Asplund et al (2005Asplund et al ( , 2009, and Sukhorukov & Shchukina (2012a).…”

Section: Introductionmentioning

confidence: 99%

Non-Lte Determination of the Silicon Abundance Using a Three-Dimensional Hydrodynamical Model of the Solar Photosphere

Shchukina

Sukhorukov

Bueno

2012

ApJ

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Confrontations of spectroscopic observations with local thermodynamic equilibrium (LTE) spectral syntheses in a three-dimensional (3D) hydrodynamical model of the solar photosphere led to a downward revision of the photospheric and meteoritic silicon abundances. Here we derive the photospheric silicon abundance taking into account non-LTE (NLTE) effects in the same 3D model. We show that the above-mentioned downward revision of the silicon abundance is caused by using the LTE approximation in the context of 3D modeling, an experimental scale of oscillator strengths, and a small number of Si i lines. We demonstrate that no revision of the solar silicon abundance is required if NLTE effects are taken into account and one uses a "solar" oscillator strength scale and an extended list of Si i lines. The NLTE abundance value we find by fitting the equivalent widths of 65 Si i lines is A NLTE Si = 7.549 ± 0.016. This value agrees well with the silicon abundance that had been recommended earlier by Grevesse & Sauval and Lodders for the solar photosphere and CI chondrite meteorites.

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“…As a consequence, solar photospheric abundance determinations are scarce in the literature. Russell (1929) determined the photospheric hafnium solar abundance to be 0.90. Recently, Lawler et al (2007) measured Hf lifetimes for several lines, four of which were used to determine a solar photospheric hafnium abundance of 0.88±0.08.…”

Section: Introductionmentioning

confidence: 99%

The solar photospheric abundance of hafnium and thorium

Caffau¹,

Sbordone²,

Ludwig³

et al. 2008

A&A

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Context. The stable element hafnium (Hf) and the radioactive element thorium (Th) were recently suggested as a suitable pair for radioactive dating of stars. The applicability of this elemental pair needs to be established for stellar spectroscopy. Aims. We aim at a spectroscopic determination of the abundance of Hf and Th in the solar photosphere based on a CO 5 BOLD 3D hydrodynamical model atmosphere. We put this into a wider context by investigating 3D abundance corrections for a set of Gand F-type dwarfs. Methods. High-resolution, high signal-to-noise solar spectra were compared to line synthesis calculations performed on a solar CO 5 BOLD model. For the other atmospheres, we compared synthetic spectra of CO 5 BOLD 3D and associated 1D models. Results. For Hf we find a photospheric abundance A(Hf) = 0.87 ± 0.04, in good agreement with a previous analysis, based on 1D model atmospheres. The weak Th ii 401.9 nm line constitutes the only Th abundance indicator available in the solar spectrum.It lies in the red wing of a Ni-Fe blend exhibiting a non-negligible convective asymmetry. Accounting for the asymmetry-related additional absorption, we obtain A(Th) = 0.08 ± 0.03, consistent with the meteoritic abundance, and about 0.1 dex lower than obtained in previous photospheric abundance determinations. Conclusions. Only for the second time, to our knowledge, has a non-negligible effect of convective line asymmetries on an abundance derivation been highlighted. Three-dimensional hydrodynamical simulations should be employed to measure Th abundances in dwarfs if similar blending is present, as in the solar case. In contrast, 3D effects on Hf abundances are small in G-to mid F-type dwarfs and sub-giants, and 1D model atmospheres can be conveniently used.

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On the Composition of the Sun's Atmosphere

Cited by 191 publications

References 0 publications

Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

Non-Lte Determination of the Silicon Abundance Using a Three-Dimensional Hydrodynamical Model of the Solar Photosphere

The solar photospheric abundance of hafnium and thorium

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