Does the anomalous solar chemical composition come from planet formation?

TL;DR

This study analyzes the chemical compositions of solar twins and compares them to the Sun, finding potential signatures of planet formation in their elemental abundance patterns, especially related to condensation temperature.

Contribution

It provides detailed abundance measurements of 19 elements in solar twins, revealing a correlation between elemental ratios and condensation temperature linked to planet formation.

Findings

Solar twins show a depletion of low Tc elements relative to the Sun.

A trend of increasing abundance with Tc observed for 900-1800 K.

Stars with similar planetary systems may be identified through chemical signatures.

Abstract

We derive the abundance of 19 elements in a sample of 64 stars with fundamental parameters very similar to solar, which minimizes the impact of systematic errors in our spectroscopic 1D-LTE differential analysis, using high-resolution (R=60,000), high signal-to-noise ratio (S/N=200) spectra. The estimated errors in the elemental abundances relative to solar are as small as 0.025 dex. The abundance ratios [X/Fe] as a function of [Fe/H] agree closely with previously established patterns of Galactic thin-disk chemical evolution. Interestingly, the majority of our stars show a significant correlation between [X/Fe] and condensation temperature (Tc). In the sample of 22 stars with parameters closest to solar, we find that, on average, low Tc elements are depleted with respect to high Tc elements in the solar twins relative to the Sun by about 0.08 dex (20%). An increasing trend is observed for the abundances as a function of Tc for 900<Tc<1800 K, while abundances of lower Tc elements appear to be roughly constant. We speculate that this is a signature of the planet formation that occurred around the Sun but not in the majority of solar twins. If this hypothesis is correct, stars with planetary systems like ours, although rare (frequency of 15%), may be identified through a very detailed inspection of the chemical compositions of their host stars.