The chemical composition of the sun1This review is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (4) ◽  
pp. 327-331 ◽  
Author(s):  
N. Grevesse ◽  
M. Asplund ◽  
A.J. Sauval ◽  
P. Scott
Keyword(s):  
Chemical Elements ◽  
Molecular Data ◽  
Solar Neighborhood ◽  
Spectral Lines ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Solar Photosphere ◽  
International Colloquium ◽  
Laboratory Plasmas ◽  
Selection Of

We have very recently re-determined the abundances of nearly all the available chemical elements in the solar photosphere, from lithium to thorium (Asplund et al. Annu. Rev. Astron. Astrophys. 47, 481 (2009)). This new complete and homogeneous analysis results from a very careful selection of spectral lines of all the indicators of the abundances present in the solar photospheric spectrum, from a discussion of the atomic and molecular data, and from an analysis of these lines based on a new 3D model of the solar outer layers, taking non-LTE effects into account when possible. We present these new results, compare them with other recent solar data as well as with recent results for the solar neighborhood, and discuss some of their most important implications as well as some of the atomic data we still urgently need.

Atomic data for stellar astrophysics: from the UV to the IR1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (4) ◽  
pp. 345-356 ◽  
Author(s):  
Glenn M. Wahlgren
Keyword(s):  
Hubble Space Telescope ◽  
Wavelength Region ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
International Colloquium ◽  
Stellar Spectra ◽  
Optical Wavelength ◽  
Laboratory Plasmas ◽  
New Instrumentation ◽  
Made In

The study of stars and stellar evolution relies heavily on the analysis of stellar spectra. The need for atomic line data from the ultraviolet (UV) to the infrared (IR) regions is greater now than ever. In the past twenty years, the time since the launch of the Hubble Space Telescope, great progress has been made in acquiring atomic data for UV transitions. The optical wavelength region, now expanded by progress in detector technology, continues to provide motivation for new atomic data. In addition, investments in new instrumentation for ground-based and space observatories has lead to the availability of high-quality spectra at IR wavelengths, where the need for atomic data is most critical. In this review, examples are provided of the progress made in generating atomic data for stellar studies, with a look to the future for addressing the accuracy and completeness of atomic data for anticipated needs.

scholarly journals The Belgian repository of fundamental atomic data and stellar spectra (BRASS)

2019 ◽  
Vol 624 ◽  
pp. A60 ◽  
Author(s):  
M. Laverick ◽  
A. Lobel ◽  
P. Royer ◽  
T. Merle ◽  
C. Martayan ◽  
...  
Keyword(s):  
Quality Assessment ◽  
Large Scale ◽  
Spectral Lines ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Chemical Abundance ◽  
Stellar Spectra ◽  
Atomic Lines ◽  
The Universe ◽  
Selection Of

Context. Fundamental atomic transition parameters, such as oscillator strengths and rest wavelengths, play a key role in modelling and understanding the chemical composition of stars in the universe. Despite the significant work under way to produce these parameters for many astrophysically important ions, uncertainties in these parameters remain large and can limit the accuracy of chemical abundance determinations.Aims. The Belgian repository of fundamental atomic data and stellar spectra (BRASS) aims to provide a large systematic and homogeneous quality assessment of the atomic data available for quantitative spectroscopy. BRASS shall compare synthetic spectra against extremely high-quality observed spectra, at a resolution of ∼85 000 and signal-noise ratios of ∼1000, for approximately 20 bright BAFGK spectral-type stars, in order to critically evaluate the atomic data available for over a thousand potentially useful spectral lines.Methods. A large-scale homogeneous selection of atomic lines is performed by synthesising theoretical spectra of literature atomic lines for FGK-type stars including the Sun, resulting in a selection of 1091 theoretically deep and unblended lines in the wavelength range 4200–6800 Å, which may be suitable for quality assessment. Astrophysical log(g f) values are determined for the 1091 transitions using two commonly employed methods. The agreement of these log(g f) values are used to select well-behaved lines for quality assessment.Results. We found 845 atomic lines to be suitable for quality assessment, of which 408 were found to be robust against systematic differences between analysis methods. Around 53% of the quality-assessed lines were found to have at least one literature log(g f) value in agreement with our derived values, though the remaining values can disagree by as much as 0.5 dex. Only ∼38% of Fe Ilines were found to have sufficiently accurate log(g f) values, increasing to ∼70–75% for the remaining Fe-group lines.

Recent progress in spectroscopy of tungsten1This review is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (5) ◽  
pp. 551-570 ◽  
Author(s):  
A. Kramida
Keyword(s):  
Energy Levels ◽  
Experimental Studies ◽  
Theoretical Data ◽  
Theoretical Work ◽  
Spectral Lines ◽  
Oscillator Strengths ◽  
International Colloquium ◽  
10Th International Colloquium ◽  
Laboratory Plasmas ◽  
Data Tables

This contribution reviews experimental and theoretical work on spectroscopy of tungsten published since the last critical compilation of the energy levels and spectral lines of highly ionized tungsten (Kramida and Shirai. At. Data Nucl. Data Tables, 95, 305 (2009)). Since then, 18 new experimental studies were published, which resulted in new identifications and (or) significantly improved wavelengths of spectral lines and energy levels of Li-like through As-like and Pm-like tungsten. A few tens of theoretical studies of tungsten spectra were published since 2008. A number of them report on high-precision calculations of energy levels, transition wavelengths, and radiative rates for tungsten spectra, such as neutral tungsten, Yb-like, Rh-like through Rb-like, Ag-like, Ga-like, Zn-like, Ni-like, Ca-like, Al-like, Mg-like, Na-like, Ne-like, B-like, Be-like, and Li-like. These developments are reviewed. Based on new experimental data, systematic errors are removed from some of the earlier measurements. Some new data are obtained by analyzing publications of other authors. Based on new published theoretical data, some old experimental results were confirmed and assessed. Revised and extended tables of energy levels and spectral lines of highly ionized tungsten are presented.

Tungsten measurement on Alcator C-Mod and EBIT for future fusion reactors1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (5) ◽  
pp. 591-597 ◽  
Author(s):  
Y.A. Podpaly ◽  
J.E. Rice ◽  
P. Beiersdorfer ◽  
M.L. Reinke ◽  
J. Clementson ◽  
...  
Keyword(s):  
Ion Trap ◽  
Oscillator Strengths ◽  
Continuum Emission ◽  
Tokamak Plasmas ◽  
Ion Temperature ◽  
International Colloquium ◽  
Plasma Facing Components ◽  
Laboratory Plasmas ◽  
Electron Beam Ion Trap ◽  
Theoretical Predictions

Tungsten will be an important element in nearly all future fusion reactors because of its presence in plasma facing components. This makes tungsten a good candidate for a diagnostic element for ion temperature and toroidal velocity measurement, and it makes understanding tungsten emissions important for tokamak power balance. The effect of tungsten on tokamak plasmas is investigated at the Alcator C-Mod tokamak using VUV, bolometry, and soft X-ray spectroscopy. Tungsten was present in Alcator C-Mod as a plasma facing component and through laser blow-off impurity injection. Quasi-continuum emission previously seen at other tokamaks has been identified. Theoretical predictions are presented of tungsten emission that could be expected in future Alcator C-Mod measurements. Furthermore, spectra of highly charged tungsten ions have been studied at the SuperEBIT electron beam ion trap. This emission could prove useful for spectroscopic diagnostics of future high-temperature fusion reactor plasmas.

Non-local thermodynamical equilibrium abundance analysis of singly ionized praseodymium for the Sun

2020 ◽  
Vol 496 (4) ◽  
pp. 5361-5371
Author(s):  
Abdelrazek M K Shaltout ◽  
Ali G A Abdelkawy ◽  
M M Beheary
Keyword(s):  
Spectral Lines ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Dimensional Model ◽  
Thermodynamical Equilibrium ◽  
Solar Abundance ◽  
One Dimensional ◽  
Microturbulent Velocity ◽  
Non Local ◽  
Local Thermodynamical Equilibrium

ABSTRACT Determinations of the solar abundance of praseodymium (Pr) depend critically on the local thermodynamical equilibrium (LTE) and non-local thermodynamical equilibrium (NLTE) techniques beyond the capabilities of a classical one-dimensional model atmosphere. Here, in this analysis, we adopt an atomic model atom of Pr consisting of 105 energy levels and 14 bound–bound transitions of singly ionized praseodymium (Pr ii) and the ground state of the Pr iii continuum limit. We briefly analyse the solar abundance of Pr taking the solar model atmospheres of Holweger & Müller (1974, Solar Physics, 39, 19) with the measured equivalent linewidths and invoking a microturbulent velocity treatment. We succeed in accurately selecting nearby clear sections of the spectrum for 14 spectral lines of Pr ii with the improved atomic data of high-quality oscillator strengths available from the laboratory measurements of several possible sources as well as accurate damping constants successfully determined from the literature. We find a Pr abundance revised to be downwards log ϵPr(NLTE) = 0.75 ± 0.09, which is in good agreement with the meteoritic value (log ϵPr = 0.76 ± 0.03). A comparison of the NLTE abundance corrections with the standard LTE analysis, log ϵPr(LTE) = 0.74 ± 0.08, reveals a positive correction of  +0.01 dex, estimated from the selected solar Pr ii lines. The Pr abundance value is clearly superior following the classical one-dimensional model atmospheres of Holweger & Müller, the absolute scales of gf-values, the microturbulent velocity and the adopted equivalent linewidths.

scholarly journals Laboratory astrophysics for the interpretation of stellar spectra

2019 ◽  
Vol 15 (S350) ◽  
pp. 345-349
Author(s):  
Ulrike Heiter
Keyword(s):  
Milky Way ◽  
Chemical Elements ◽  
Spectral Lines ◽  
Laboratory Astrophysics ◽  
Atomic Data ◽  
Milky Way Galaxy ◽  
Infrared Wavelength ◽  
Stellar Spectra ◽  
Continuous Activities ◽  
Host Stars

AbstractHigh-resolution stellar spectra are important tools for studying the chemical evolution of the Milky Way Galaxy, tracing the origin of chemical elements, and characterizing planetary host stars. Large amounts of data have been accumulating, in particular in the optical and infrared wavelength regions. The observed spectral lines are interpreted using model spectra that are calculated based on transition data for numerous species, in particular neutral and singly ionized atoms. We rely heavily on the continuous activities of laboratory astrophysics groups that produce high-quality experimental and theoretical atomic data for the relevant transitions. We give examples for the precision with which the chemical composition of stars observed by different surveys can be determined, and discuss future needs from laboratory astrophysics.

Plasma polarization spectroscopy of atomic and molecular emissions from magnetically confined plasmas1This review is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (5) ◽  
pp. 495-501 ◽  
Author(s):  
T. Shikama ◽  
K. Fujii ◽  
S. Kado ◽  
H. Zushi ◽  
M. Sakamoto ◽  
...  
Keyword(s):  
Zeeman Splitting ◽  
Oscillator Strengths ◽  
Balmer Series ◽  
International Colloquium ◽  
Polarization Spectroscopy ◽  
Laboratory Plasmas ◽  
Magnetically Confined ◽  
Band Spectra ◽  
The Magnetic Field ◽  
Α Band

In spectroscopic measurements of magnetically confined torus plasmas, the line-integrated emission along a viewing chord is usually observed. However, by utilizing the dependence of the magnitude of the Zeeman splitting on the emission location, a few localized emissions existing along the viewing chord can be separated. A detailed analysis of the Zeeman split spectral lineshapes then makes it possible to evaluate the local values of the magnetic field strength, population density, temperature, and flow velocity. We have introduced polarization spectroscopy to improve the accuracy in separating the overlapped spectra. The polarization resolved Hα, He I, and H2 Fulcher-α band spectra are measured in the TRIAM-1M tokamak, and the atomic and molecular dynamics are investigated. Further progress in the simultaneous measurements of the Balmer series and Fulcher-α band spectra in LHD, and extension to the CH Gerö band spectra, are briefly presented.

The 3s23p3d 3Fo term in the Si-like spectrum of Fe (Fe XIII)1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (4) ◽  
pp. 403-412 ◽  
Author(s):  
Elmar Träbert ◽  
Yasuyuki Ishikawa ◽  
Juan A. Santana ◽  
Giulio Del Zanna
Keyword(s):  
Fine Structure ◽  
Ab Initio Calculations ◽  
Solar Corona ◽  
Ab Initio ◽  
Oscillator Strengths ◽  
Special Issue ◽  
International Colloquium ◽  
10Th International Colloquium ◽  
Laboratory Plasmas ◽  
Cast Doubt

The structure of Si-like ions is discussed for the example of iron (spectrum Fe XIII). The 3s23p3d 3Fo term with its three fine structure levels of very different lifetimes has eluded the early observations. Meanwhile, complementary experimental techniques have permitted to track these levels. Theory has also evolved from approximate techniques to accurate ab initio calculations, the results of which cast doubt on some earlier Fe XIII line identifications and guide the search for and the identification of the correct lines in solar corona spectra.

On the interpretation of complex atomic spectra by means of the parametric Racah–Slater method and Cowan codes1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (4) ◽  
pp. 451-456 ◽  
Author(s):  
Jean-François Wyart
Keyword(s):  
Transition Probabilities ◽  
Energy Levels ◽  
Lanthanide Ions ◽  
Oscillator Strengths ◽  
Effective Parameters ◽  
International Colloquium ◽  
Atomic Spectra ◽  
Laboratory Plasmas ◽  
New Energy ◽  
Electronic Configurations

Theoretical studies of electronic configurations of several lanthanide ions in the Racah–Slater approach were performed with the standard suite of codes by R.D. Cowan, including a fitting of energy parameters. Configuration interaction was considered explicitly in the low configurations and was processed by effective parameters for doubly-excited far configurations. Mean errors lower than 100 cm–1 were obtained. Systematic differences are noticed between radial integrals calculated by ab initio PHFR and the Pfit fitted values. The consistency of the scaling factors SF(P) = Pfit/PHFR and of the effective parameters for far configuration effects is shown. In an application to Tm II, the predicted transition probabilities compared well with line intensities and led to the finding of new energy levels. In Nd II, the configuration 4f5 is identified.

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