The Sun's chemical peculiarity: disentangling Galactic chemical evolution and planetary engulfment in solar twins
Abstract
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 solar twins using a differential spectroscopic approach and Bayesian framework to test whether the Sun's chemical peculiarity arises from Galactic chemical evolution (GCE) or planetary ingestion. Using the spectroscopic tool Korg, we obtain highly precise, validated atmospheric parameters and abundances for 18 elements, with an average abundance 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. Our results indicate that the 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.
Versions
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BibTeX
@misc{babatsikos2026suns,
title = {{The Sun's chemical peculiarity: disentangling Galactic chemical evolution and planetary engulfment in solar twins}},
author = {Mia Babatsikos and Fan Liu and Amanda Karakas and Ilya Mandel and Lachlan Passenger and Megan Bedell and Sharon Wang and Zimo Cheng},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2607.01699},
eprint = {2607.01699},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.01699},
}
RIS
TY - UNPB
TI - The Sun's chemical peculiarity: disentangling Galactic chemical evolution and planetary engulfment in solar twins
AU - Mia Babatsikos
AU - Fan Liu
AU - Amanda Karakas
AU - Ilya Mandel
AU - Lachlan Passenger
AU - Megan Bedell
AU - Sharon Wang
AU - Zimo Cheng
PY - 2026
DA - 2026/09/07
PB - arXiv
DO - 10.48550/arxiv.2607.01699
UR - https://arxiv.org/abs/2607.01699
AB - 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 solar twins using a differential spectroscopic approach and Bayesian framework to test whether the Sun's chemical peculiarity arises from Galactic chemical evolution (GCE) or planetary ingestion. Using the spectroscopic tool Korg, we obtain highly precise, validated atmospheric parameters and abundances for 18 elements, with an average abundance 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. Our results indicate that the 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.
ER -