Fe I Oscillator Strengths for Transitions from High-lying Even-Parity Levels

TL;DR

This paper reports new precise measurements of radiative lifetimes and oscillator strengths for Fe I transitions, improving atomic data crucial for astrophysical spectral analysis and solar abundance determinations.

Contribution

It provides new radiative lifetimes and oscillator strengths for Fe I levels, extending previous work and enhancing atomic data accuracy for astrophysical applications.

Findings

New radiative lifetimes measured with ±5% accuracy.

Oscillator strengths for 203 Fe I lines derived.

Solar iron abundance estimated as log[ε(Fe)] = 7.45 ± 0.06.

Abstract

New radiative lifetimes, measured to $\pm$ 5 % accuracy, are reported for 31 even-parity levels of Fe I ranging from 45061 cm$^{-1}$ to 56842 cm$^{-1}$. These lifetimes have been measured using single-step and two-step time-resolved laser-induced fluorescence on a slow atomic beam of iron atoms. Branching fractions have been attempted for all of these levels, and completed for 20 levels. This set of levels represents an extension of the collaborative work reported in Ruffoni et al. (2014). The radiative lifetimes combined with the branching fractions yields new oscillator strengths for 203 lines of Fe I. Utilizing a 1D-LTE model of the solar photosphere, spectral syntheses for a subset of these lines which are unblended in the solar spectrum yields a mean iron abundance of <log[{\epsilon}(Fe)]> = 7.45 $\pm$ 0.06.