Unprecedented accurate abundances: signatures of other Earths?

TL;DR

This study reveals the Sun's unique chemical composition, showing a depletion of refractory elements likely linked to terrestrial planet formation, based on highly precise abundance measurements compared to solar twins and analogs.

Contribution

It provides the first highly precise differential abundance analysis showing the Sun's peculiar composition related to terrestrial planet formation.

Findings

The Sun has a ~20% depletion of refractory elements compared to solar twins.

The abundance pattern correlates with element condensation temperatures.

Solar analogs with close-in giant planets do not show this depletion.

Abstract

For more than 140 years the chemical composition of our Sun has been considered typical of solar-type stars. Our highly differential elemental abundance analysis of unprecedented accuracy (~0.01 dex) of the Sun relative to solar twins, shows that the Sun has a peculiar chemical composition with a ~20% depletion of refractory elements relative to the volatile elements in comparison with solar twins. The abundance differences correlate strongly with the condensation temperatures of the elements. A similar study of solar analogs from planet surveys shows that this peculiarity also holds in comparisons with solar analogs known to have close-in giant planets while the majority of solar analogs without detected giant planets show the solar abundance pattern. The peculiarities in the solar chemical composition can be explained as signatures of the formation of terrestrial planets like our own Earth.