Mg/Si mineralogical ratio of low-mass planet hosts. Correction for the NLTE effects

TL;DR

This study applies non-LTE corrections to stellar Mg and Si abundances to investigate differences in Mg/Si ratios between stars hosting low-mass planets and those without planets, revealing a potential link to planet formation efficiency.

Contribution

It introduces non-LTE corrections to Mg and Si abundances and confirms the higher Mg/Si ratio in stars hosting super-Earth and Neptune-mass planets compared to non-host stars.

Findings

Higher Mg/Si ratios are found in planet-hosting stars.

Small stellar parameter differences do not explain Mg/Si variations.

High Mg/Si ratios may relate to planet formation environments.

Abstract

Mg/Si and Fe/Si ratios are important parameters that control the composition of rocky planets. In this work we applied non-LTE correction to the Mg and Si abundances of stars with and without planets to confirm/infirm our previous findings that [Mg/Si] atmospheric abundance is systematically higher for Super-Earth/Neptune-mass planet hosts than stars without planets. Our results show that the small differences of stellar parameters observed in these two groups of stars are not responsible for the already reported difference in the [Mg/Si] ratio. Thus, the high [Mg/Si] ratio of Neptunian hosts is probably related to the formation efficiency of these planets in such environments.