Iron abundance in the atmosphere of Arcturus

TL;DR

This study precisely measures the iron abundance in Arcturus's atmosphere using high-resolution spectral analysis and theoretical modeling, providing insights into its chemical composition relative to the Sun.

Contribution

It introduces a method combining spectral line synthesis with MARCS models to accurately determine stellar iron abundance and macroturbulent velocity.

Findings

Iron abundance in Arcturus: A=6.95±0.03

Relative iron abundance [Fe/H]: -0.48±0.02

Macroturbulent velocity in Arcturus: 5.6±0.2 km/s

Abstract

Abundance of iron in the atmosphere of Arcturus has been determined from the profiles or regions of the profiles of the weak lines sensitive to iron abundance. The selected lines of Fe I and Fe II were synthesized with the MARCS theoretical models of the atmosphere. From the observed profiles of lines available with a high spectral resolution in the atlas by Hinkle and Wallace (2005), the values of the iron abundance $A = 6.95 \pm 0.03$ and the radial-tangential macroturbulent velocity $5.6 \pm 0.2$ km/s were obtained for Arcturus. The same physical quantities were found for the Sun as a star; they are $7.42 \pm 0.02$ and $3.4 \pm 0.3$ km/s, respectively. For Arcturus, the iron abundance relative to the solar one was determined with the differential method as [Fe/H] $=-0.48 \pm 0.02$.