A revision of the solar manganese abundance using new and remeasured laboratory oscillator strengths

Abstract

Context. The solar photospheric element abundances are generally in good agreement with the meteoritic CI chondrite abundances, with the exception of a small number of elements including manganese. The solar photospheric abundances, determined using model atmospheres, include laboratory oscillator strengths where available. However, the current laboratory database for Mn I oscillator strengths is derived from several different laboratory observations determined from several different laboratory techniques. The uncertainty in the solar photospheric manganese abundance and the difference between it and the meteoritic CI chondrite abundance may just be an artefact of inaccurate laboratory data. Aims. The aim of our new laboratory measurements is to measure a self consistent set of accurate absolute oscillator strengths and use the new laboratory data to re-evaluate the solar manganese abundance. Methods. New and more accurate oscillator strengths have been determined by combining branching fractions with previously measured energy level lifetimes. Using the new laboratory data, the solar photospheric abundance of manganese has been determined with theoretical and semi-empirical model atmospheres, MAFAGS-ODF and Holweger & Müller, respectively. Results. We present experimental oscillator strengths for 94 Mn I transitions covering the wavelength range 2384 to 17 744 Å. Using 22 relatively un-blended solar Mn I transitions, we determine the photospheric abundance of manganese to be log ε ⊙ = 5.37 ± 0.05 dex. Conclusions. The new value is in good agreement with previous photospheric abundance determinations. The implications for the solar photospheric and meteoritic CI chondrite abundance is discussed. © ESO 2007.