Fe I Oscillator Strengths for the Gaia-ESO Survey

TL;DR

This paper provides new experimental oscillator strengths for Fe I lines crucial for the Gaia-ESO Survey, improving stellar abundance measurements and spectral modeling accuracy.

Contribution

It introduces 142 experimentally derived Fe I oscillator strengths, addressing missing data in atomic databases for large-scale stellar surveys.

Findings

New Fe I oscillator strengths improve spectral modeling.

Fe abundance measurements show low scatter and good agreement with literature.

Enhanced atomic data supports more accurate stellar chemical analyses.

Abstract

The Gaia-ESO Public Spectroscopic Survey (GES) is conducting a large-scale study of multi-element chemical abundances of some 100 000 stars in the Milky Way with the ultimate aim of quantifying the formation history and evolution of young, mature and ancient Galactic populations. However, in preparing for the analysis of GES spectra, it has been noted that atomic oscillator strengths of important Fe I lines required to correctly model stellar line intensities are missing from the atomic database. Here, we present new experimental oscillator strengths derived from branching fractions and level lifetimes, for 142 transitions of Fe I between 3526 {\AA} and 10864 {\AA}, of which at least 38 are urgently needed by GES. We also assess the impact of these new data on solar spectral synthesis and demonstrate that for 36 lines that appear unblended in the Sun, Fe abundance measurements yield a small line-by-line scatter (0.08 dex) with a mean abundance of 7.44 dex in good agreement with recent publications.