No statistically significant evidence for a correlation between stellar and planetary composition
Abstract
The chemical compositions of planets and their hosts stars are intrinsically linked, having formed from the same protostellar material. Characterising this relationship provides key constraints on the processes governing planetary formation and evolution. Focusing on host stars with near-solar chemical abundances limits our understanding of how planetary composition varies across a broader chemical parameter space. Expanding the sample to include stars with compositions markedly different from the Sun is therefore essential for building a complete picture of star--planet compositional connections. Here, we focus specifically on iron-poor hosts since they are more likely to be alpha-enhanced and represent some of the most chemically distinct stars relative to the Sun (i.e., thick disc stars). We present a sample of 45 stars hosting 64 planets across the super-Earth and sub-Neptune regimes, for which we homogeneously obtain new stellar parameters including abundances, re-derive planetary mass and radius, and model the bulk interior compositions of their planetary companions. No statistically significant evidence for a correlation between stellar and planetary composition was found in our sample. We suggest that this null result is primarily driven by the large uncertainties inherent to both compositional proxies, which may obscure an underlying relationship. Quantifying these uncertainties is therefore a critical step that previous studies have not fully addressed. Furthermore, even with improved precision, uncovering such a relation may require a higher-dimensional treatment that accounts for additional parameters such as planetary equilibrium temperature.
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BibTeX
@misc{turner2026statistically,
title = {{No statistically significant evidence for a correlation between stellar and planetary composition}},
author = {Daisy A. Turner and Annelies Mortier and James G. Rogers and Jo Ann Egger and Alix V. Freckelton and Tim Lichtenberg and Anjali A. A. Piette},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.17159},
eprint = {2609.17159},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.17159},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - No statistically significant evidence for a correlation between stellar and planetary composition
AU - Daisy A. Turner
AU - Annelies Mortier
AU - James G. Rogers
AU - Jo Ann Egger
AU - Alix V. Freckelton
AU - Tim Lichtenberg
AU - Anjali A. A. Piette
PY - 2026
DA - 2026/09/15
PB - arXiv
DO - 10.48550/arxiv.2609.17159
UR - https://arxiv.org/abs/2609.17159
AB - The chemical compositions of planets and their hosts stars are intrinsically linked, having formed from the same protostellar material. Characterising this relationship provides key constraints on the processes governing planetary formation and evolution. Focusing on host stars with near-solar chemical abundances limits our understanding of how planetary composition varies across a broader chemical parameter space. Expanding the sample to include stars with compositions markedly different from the Sun is therefore essential for building a complete picture of star--planet compositional connections. Here, we focus specifically on iron-poor hosts since they are more likely to be alpha-enhanced and represent some of the most chemically distinct stars relative to the Sun (i.e., thick disc stars). We present a sample of 45 stars hosting 64 planets across the super-Earth and sub-Neptune regimes, for which we homogeneously obtain new stellar parameters including abundances, re-derive planetary mass and radius, and model the bulk interior compositions of their planetary companions. No statistically significant evidence for a correlation between stellar and planetary composition was found in our sample. We suggest that this null result is primarily driven by the large uncertainties inherent to both compositional proxies, which may obscure an underlying relationship. Quantifying these uncertainties is therefore a critical step that previous studies have not fully addressed. Furthermore, even with improved precision, uncovering such a relation may require a higher-dimensional treatment that accounts for additional parameters such as planetary equilibrium temperature.
ER -