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

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.

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V. Adibekyan, H. Silva, S. Santos, et. al.
Mon, 17 Jul 17

Comments: In press. Astrophysics, Vol. 60, No. 3, September , 2017