The Belgian repository of fundamental atomic data and stellar spectra (BRASS) II. Quality assessment of atomic data for unblended lines in FGK stars

Abstract

Fundamental atomic transition parameters, such as oscillator strengths and 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 ions, uncertainties in these parameters remain large and can limit the accuracy of chemical abundance determinations. 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 ~85000 and signal-noise ratios of ~1000, for around 20 bright BAFGK spectral type stars, in order to evaluate the atomic data available for over a thousand potentially useful spectral lines. 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(gf) values are determined for the 1091 transitions using two commonly employed methods. The agreement of these log(gf) values are used to select well-behaving lines for quality assessment. 845 atomic lines were found to be suitable for quality assessment, of which 408 were found to be robust against systematic differences between analysis methods. Around 54% of the quality-assessed lines were found to have at least one literature log(gf) value in agreement with our derived values, though the remaining values can disagree by as much as 0.5 dex. Only 38% of FeI lines were found to have sufficiently accurate log(gf) values, increasing to ~70-75% for the remaining Fe-group lines.

arXiv comment15 pages + 35 appendix pages, 20 figures, 6 tables. Full appendix tables available via CDS

References in corpus (28)

• The Gaia mission
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The GALAH Survey: Scientific Motivation
• HERMES: a high-resolution fibre-fed spectrograph for the Mercator telescope
• NLTE line formation of Fe in late-type stars II: 1D spectroscopic stellar parameters
• Spectral Properties of Cool Stars: Extended Abundance Analysis of 1617 Planet Search Stars
• A new code for automatic determination of equivalent widths: Automatic Routine for line Equivalent widths in stellar Spectra (ARES)
• Both accurate and precise gf-values for FeII lines
• 4MOST - 4-metre Multi-Object Spectroscopic Telescope
• Improved Laboratory Transition Probabilities for Neutral Chromium and Re-determination of the Chromium Abundance for the Sun and Three Stars
• Improved Laboratory Transition Probabilities for Ce II, Application to the Cerium Abundances of the Sun and Five r-process Rich, Metal-Poor Stars, and Rare Earth Lab Data
• Abundances in the Local Region II: F, G and K Dwarfs and Subgiants
• Improved Ti II log(gf) Values and Abundance Determinations in the Photospheres of the Metal-Poor Star HD 84937
• Fe I Oscillator Strengths for the Gaia-ESO Survey
• Accurate abundance analysis of late-type stars: advances in atomic physics
• Improved Ni I log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937
• M-dwarf metallicities - A high-resolution spectroscopic study in the near infrared
• SP_Ace: a new code to derive stellar parameters and elemental abundances
• Homogeneous abundance analysis of dwarf, subgiant and giant FGK stars with and without giant planets
• A NLTE line formation for neutral and singly-ionised titanium in model atmospheres of the reference A-K stars
• BayeSED: A General Approach to Fitting the Spectral Energy Distribution of Galaxies
• Fe II lifetimes and transition probabilities
• Experimental Ti I oscillator strengths and their application to cool star analysis
• The case for high precision in elemental abundances of stars in the era of large spectroscopic surveys
• Atmospheric stellar parameters for large surveys using FASMA, a new spectral synthesis package
• NIR spectroscopy of the Sun and HD20010 - Compiling a new linelist in the NIR
• SpectroWeb: Oscillator Strength Measurements of Atomic Absorption Lines in the Sun and Procyon
• The Belgian repository of fundamental atomic data and stellar spectra (BRASS). I. Cross-matching atomic databases of astrophysical interest

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