The solar photospheric abundance of europium. Results from CO5BOLD 3-D hydrodynamical model atmospheres

TL;DR

This study accurately determines the solar europium abundance using advanced 3D hydrodynamical models, confirming previous 1D model results and showing negligible 3D effects for europium in the Sun.

Contribution

First to derive solar europium abundance with CO5BOLD 3D models, validating previous 1D results and analyzing isotopic fractions and 3D corrections across stellar parameters.

Findings

Europium abundance is 0.52 +- 0.02, consistent with previous studies.

Isotopic fraction of Eu(151) is approximately 50%, matching meteoritic data.

3D corrections are negligible for the Sun and similar stars.

Abstract

Context. Europium is an almost pure r-process element, which may be useful as a reference in nucleocosmochronology. Aims. To determine the photospheric solar abundance using CO5BOLD 3-D hydrodynamical model atmospheres. Methods. Disc-centre and integrated-flux observed solar spectra are used. The europium abundance is derived from the equivalent width measurements. As a reference 1D model atmospheres have been used, in addition. Results. The europium photospheric solar abundance is 0.52 +- 0.02 in agreement with previous determinations. We also determine the photospheric isotopic fraction of Eu(151) to be 49 % +- 2.3 % from the intensity spectra and 50% +-2.3 from the flux spectra. This compares well to the the meteoritic isotopic fraction 47.8%. We explore the 3D corrections also for dwarfs and sub-giants in the temperature range ~5000 K to ~6500 K and solar and 1/10--solar metallicities and find them to be negligible for all the models investigated. Conclusions. Our photospheric Eu abundance is in good agreement with previous determinations based on 1D models. This is in line with our conclusion that 3D effects for this element are negligible in the case of the Sun.