Solar oxygen abundance

Bergemann, M.; Hoppe, R.; Semenova, Ekaterina; Carlsson, Mats; Yakovleva, Svetlana A.; Voronov, Yaroslav V.; Bautista, M. A.; Nemer, Ahmad; Belyaev, Andrey K.; Leenaarts, J.; Mashonkina, L.; Reiners, A.; Ellwarth, M.

doi:10.1093/mnras/stab2160

Cited by 59 publications

(72 citation statements)

References 82 publications

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“…While early work based on imposed vertical magnetic fields implied that the effects could be substantial (Fabbian et al 2010), more recent 3D LTE calculations based on a 3D MHD solar model with a self-consistent small-scale magnetic dynamo (Rempel 2014) reveal that the impact on solar abundance determination is negligible (<0.01 dex) at least for C, N, O, and Fe (Shchukina & Trujillo Bueno 2015;Shchukina et al 2016); this may not hold however for elements in which non-LTE effects are important and thus deserves further scrutiny. Similarly, there is no indication that the inclusion of a chromosphere or other magnetic activity in the solar model would significantly impact the derived abundances for the weak photospheric lines employed here using disc-centre observations of the quiet Sun (Bergemann et al 2021).…”

Section: Discussionmentioning

confidence: 91%

The chemical make-up of the Sun: A 2020 vision

Asplund

Amarsi

Grevesse

2021

A&A

337

270

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Context. The chemical composition of the Sun is a fundamental yardstick in astronomy, relative to which essentially all cosmic objects are referenced. As such, having accurate knowledge of the solar elemental abundances is crucial for an extremely broad range of topics. Aims. We reassess the solar abundances of all 83 long-lived elements, using highly realistic solar modelling and state-of-the-art spectroscopic analysis techniques coupled with the best available atomic data and observations. Methods. The basis for our solar spectroscopic analysis is a three-dimensional (3D) radiative-hydrodynamical model of the solar surface convection and atmosphere, which reproduces the full arsenal of key observational diagnostics. New complete and comprehensive 3D spectral line formation calculations taking into account of departures from local thermodynamic equilibrium (non-LTE) are presented for Na, Mg, K, Ca, and Fe using comprehensive model atoms with reliable radiative and collisional data. Our newly derived abundances for C, N, and O are based on a 3D non-LTE analysis of permitted and forbidden atomic lines as well as 3D LTE calculations for a total of 879 molecular transitions of CH, C2, CO, NH, CN, and OH. Previous 3D-based calculations for another 50 elements are re-evaluated based on updated atomic data, a stringent selection of lines, improved consideration of blends, and new non-LTE calculations available in the literature. For elements where spectroscopic determinations of the quiet Sun are not possible, the recommended solar abundances are revisited based on complementary methods, including helioseismology (He), solar wind data from the Genesis sample return mission (noble gases), sunspot observations (four elements), and measurements of the most primitive meteorites (15 elements). Results. Our new improved analysis confirms the relatively low solar abundances of C, N, and O obtained in our previous 3D-based studies: log ϵC = 8.46 ± 0.04, log ϵN = 7.83 ± 0.07, and log ϵO = 8.69 ± 0.04. Excellent agreement between all available atomic and molecular indicators is achieved for C and O, but for N the atomic lines imply a lower abundance than for the molecular transitions for unknown reasons. The revised solar abundances for the other elements also typically agree well with our previously recommended values, with only Li, F, Ne, Mg, Cl, Kr, Rb, Rh, Ba, W, Ir, and Pb differing by more than 0.05 dex. The here-advocated present-day photospheric metal mass fraction is only slightly higher than our previous value, mainly due to the revised Ne abundance from Genesis solar wind measurements: Xsurface = 0.7438 ± 0.0054, Ysurface = 0.2423 ± 0.0054, Zsurface = 0.0139 ± 0.0006, and Zsurface/Xsurface = 0.0187 ± 0.0009. Overall, the solar abundances agree well with those of CI chondritic meteorites, but we identify a correlation with condensation temperature such that moderately volatile elements are enhanced by ≈0.04 dex in the CI chondrites and refractory elements possibly depleted by ≈0.02 dex, conflicting with conventional wisdom of the past half-century. Instead, the solar chemical composition more closely resembles that of the fine-grained matrix of CM chondrites with the expected exception of the highly volatile elements. Conclusions. Updated present-day solar photospheric and proto-solar abundances are presented for 83 elements, including for all long-lived isotopes. The so-called solar modelling problem – a persistent discrepancy between helioseismology and solar interior models constructed with a low solar metallicity similar to that advocated here – remains intact with our revised solar abundances, suggesting shortcomings with the computed opacities and/or treatment of mixing below the convection zone in existing standard solar models. The uncovered trend between the solar and CI chondritic abundances with condensation temperature is not yet understood but is likely imprinted by planet formation, especially since a similar trend of opposite sign is observed between the Sun and solar twins.

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Section: Discussionmentioning

confidence: 91%

The chemical make-up of the Sun: A 2020 vision

Asplund

Amarsi

Grevesse

2021

A&A

337

270

View full text Add to dashboard Cite

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“…More recently, Bergemann et al (2021) have studied the O i 777 nm triplet lines and the [O i] 630 nm line, using 13 snapshots of the 3D model solar atmosphere from the STAGGERgrid (Collet et al 2011;Magic et al 2013). This 3D model is similar to that employed in Amarsi et al (2018Amarsi et al ( , 2019Amarsi et al ( , 2020b as well as in the present study: It was computed with the STAGGER code, employing the standard solar chemical composition of Asplund et al (2009); the 13 snapshots have a mean effective temperature of 5773 K. The authors employed columnby-column non-LTE radiative transfer (the so-called 1.5D non-LTE approach); Fig.…”

Section: Comparison With Atomic Resultsmentioning

confidence: 99%

The solar carbon, nitrogen, and oxygen abundances from a 3D LTE analysis of molecular lines

Amarsi

Grevesse

Asplund

et al. 2021

A&A

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Carbon, nitrogen, and oxygen are the fourth, sixth, and third most abundant elements in the Sun. Their abundances remain hotly debated due to the so-called solar modelling problem that has persisted for almost 20 years. We revisit this issue by presenting a homogeneous analysis of 408 molecular lines across 12 diagnostic groups, observed in the solar intensity spectrum. Using a realistic 3D radiative-hydrodynamic model solar photosphere and local thermodynamic equilibrium (LTE) line formation, we find log ϵC = 8.47 ± 0.02, log ϵN = 7.89 ± 0.04, and log ϵO = 8.70 ± 0.04. The stipulated uncertainties mainly reflect the sensitivity of the results to the model atmosphere; this sensitivity is correlated between the different diagnostic groups, which all agree with the mean result to within 0.03 dex. For carbon and oxygen, the molecular results are in excellent agreement with our 3D non-LTE analyses of atomic lines. For nitrogen, however, the molecular indicators give a 0.12 dex larger abundance than the atomic indicators, and our best estimate of the solar nitrogen abundance is given by the mean: 7.83 dex. The solar oxygen abundance advocated here is close to our earlier determination of 8.69 dex, and so the present results do not significantly alleviate the solar modelling problem.

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“…The 6300.3 Å oxygen forbidden line is known to be unaffected by non-LTE and shows little sensitivity to 3D effects (Asplund 2004;Pereira et al 2009). This line forms nearly in LTE and is only weakly sensitive to convection, its formation is similar in 3D radiation hydrodynamic and 3D magnetoradition-hydrodynamical solar models (Bergemann et al 2021). Threfore, possible non-LTE effects on [C/O] should be very small.…”

Section: Kinematic Propertiesmentioning

confidence: 98%

Chemical Composition Of Bright Stars In The Northern Hemisphere: Star-Planet Connection

Tautvaišienė,

Mikolaitis,

Drazdauskas

et al. 2022

Preprint

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In fulfilling the aims of the planetary and asteroseismic research missions, such as that of the NASA Transiting Exoplanet Survey Satellite (TESS) space telescope, accurate stellar atmospheric parameters and a detailed chemical composition are required as input. We have observed high-resolution spectra for all 848 bright (V < 8 mag) stars that are cooler than F5 spectral class in the area up to 12 deg surrounding the northern TESS continuous viewing zone and uniformly determined the main atmospheric parameters, ages, orbital parameters, velocity components, and precise abundances of up to 24 chemical species (C(C 2 ), N(CN), [O

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Solar oxygen abundance

Cited by 59 publications

References 82 publications

The chemical make-up of the Sun: A 2020 vision

The chemical make-up of the Sun: A 2020 vision

The solar carbon, nitrogen, and oxygen abundances from a 3D LTE analysis of molecular lines

Chemical Composition Of Bright Stars In The Northern Hemisphere: Star-Planet Connection

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