Chemical signatures of planet engulfment in solar twins

Recent observational studies have suggested that the Sun may be chemically peculiar relative to the majority of solar twins. Here, we re-analyse high-resolution, high signal-to-noise spectra of 79 nearby, non-co-natal solar twins using a differential spectroscopic approach and Bayesian framework to test whether the Sun's apparent chemical peculiarity arises from Galactic chemical evolution (GCE) or planetary ingestion. Using new spectroscopic tool Korg, we obtain highly precise, validated atmospheric parameters and abundances for 18 elements, with an average precision of 0.015dex (3.5%). Employing an independent Bayesian indicator, we disentangle GCE and planetary engulfment signatures from other processes influencing stellar composition, including intrinsic abundance scatter, and primordial compositional differences. Our results indicate that the apparent chemical peculiarity of the Sun relative to the average solar twin is largely driven by GCE effects, with 62.3+-5.8% of our sample exhibiting abundance patterns well described by GCE trends. We further identify 2-6 solar twin candidates exhibiting chemical signatures consistent with planetary engulfment that warrant further investigation. These findings reinforce the importance of accounting for GCE effects when interpreting solar twin abundance patterns, and suggest that the Sun may not be chemically peculiar relative to the majority of solar twins.