  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.
