Iron abundance in the solar photosphere. Application of a two-component model atmosphere

¹ Kiepenheuer–Institut für Sonnenphysik, Schöneckstr. 6, 79104, Freiburg, Germany
² Max–Planck Institut für Aeronomie, 37191, Katlenburg–Lindau, Germany

Corresponding author: L. R. Bellot Rubio, lbellot@kis.uni-freiburg.de

Received: 4 March 2002
Accepted: 23 April 2002

Abstract

A realistic two-component model of the quiet Sun is used to determine the solar abundance of iron from the inversion of a number of Fe I and Fe II spectral lines for which accurate atomic parameters (oscillator strengths, central wavelengths, and collisional broadening cross sections) exist. From 33 Fe I lines we infer an abundance of , whereas we estimate from 10 Fe II lines. These values are in excellent agreement with the results of analyses based on realistic 3D hydrodynamical simulations of the solar granulation, and imply a low photospheric iron abundance. We investigate the effects of convective motions and granular temperatures and conclude that both are important for reliable abundance determinations. For Fe I lines, the effects of convective motions can be simulated by using a microturbulent velocity of about 1 km s^-1, whereas it is possible to account for temperature inhomogeneities by adopting an average temperature stratification which is cooler than the Holweger & Müller model in the upper layers.