Vanadium Transitions in the Spectrum of Arcturus

Wood, Michael P.; Sneden, Christopher; Lawler, J. E.; Hartog, E. A. Den; Cowan, J. J.; Nave, Gillian

doi:10.3847/1538-4365/aa9a41

Cited by 18 publications

(21 citation statements)

References 44 publications

(57 reference statements)

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“…few available V ii lines due to their heavy blending, although nominally they suggest a ≈0.1 dex higher V abundance, both in 3D and 1D. Updating the Scott et al (2015a) results with the Lawler et al (2014) and Wood et al (2014a) experimental g fvalues, the mean V i abundance is only +0.01 dex higher, while the V ii result changes by −0.02 dex 8 . We caution that our ad hoc V i non-LTE correction may well be underestimated, and we strongly encourage the first non-LTE investigation of this element to be performed.…”

Section: Intermediate-mass Elements: Sodium To Calciummentioning

confidence: 78%

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

Asplund

Amarsi

Grevesse

2021

A&A

332

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: Intermediate-mass Elements: Sodium To Calciummentioning

confidence: 78%

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

Asplund

Amarsi

Grevesse

2021

A&A

332

270

View full text Add to dashboard Cite

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“…This star has both excellent high-resolution spectroscopic atlases and careful model atmosphere studies. The reader is referred to [48] for citations to these studies and a discussion of V I transitions in the red spectral region of Arcturus. In Figure 4, we present abundances for 168 Ti I lines in Arcturus from 5200 Å to 2.4 µm.…”

Section: Extending the Wavelength Domain To The Near-infraredmentioning

confidence: 99%

“…Examination of the solar photospheric spectrum [49] has called attention of the isotopic substructure of Ti I transitions, which have been previously reported in laboratory studies (e.g., [50]). In solar-system material, Ti splits into these isotopes: 46 Ti, 8.25%; 47 Ti, 7.44%; 48 Ti, 73.72%; 49 Ti, 5.41%; and 50 Ti, 5.18%.…”

Section: Extending the Wavelength Domain To The Near-infraredmentioning

confidence: 99%

Application of Laboratory Atomic Physics to Some Significant Stellar Chemical Composition Questions

Sneden

Lawler

Wood

2018

Atoms

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This brief review highlights some current issues in Galactic stellar nucleosynthesis, and some recent laboratory studies by the Wisconsin atomic physics group that have direct application to stellar spectroscopy to advance our understanding of the chemical evolution of our Galaxy. The relevant publication history of the lab studies are summarized, and investigations into the abundances of neutron-capture and iron-peak elements in low metallicity stars are described. Finally, new initiatives in near-infrared spectroscopy are briefly explored.

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“…This star has both excellent high-resolution spectroscopic atlases and careful model atmosphere studies. The reader is referred to [41] for citations to these studies and a discussion of V I transitions in the red spectral region of Arcturus.…”

Section: Extending the Wavelength Domain To The Near-infraredmentioning

confidence: 99%

Application of Laboratory Atomic Physics to Some Significant Stellar Chemical Composition Questions

Sneden¹,

Lawler²,

Wood³

2018

Preprint

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This brief review highlights some current issues in Galactic stellar nucleosynthesis, and 1 some recent laboratory studies by the Wisconsin atomic physics group that have direct application 2 to stellar spectroscopy, in order to advance our understanding of the chemical evolution of our 3 Galaxy. The relevant publication history of the lab studies are summarized, and investigations into 4 the abundances of neutron-capture and iron-peak elements in low metallicity stars are described. 5Finally, new initatives in near-infrared spectroscopy are briefly explored.

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Vanadium Transitions in the Spectrum of Arcturus

Cited by 18 publications

References 44 publications

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

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

Application of Laboratory Atomic Physics to Some Significant Stellar Chemical Composition Questions

Application of Laboratory Atomic Physics to Some Significant Stellar Chemical Composition Questions

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