Mind the Companion : Demographics of Transiting S-type Exoplanets

Fuente: arXiv
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Main Authors: Messamah, Lina Y., Bouchy, François, Venturini, Julia, Parc, Léna, Nigioni, Ariana
Format: Preprint
Published: 2026
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author Messamah, Lina Y.
Bouchy, François
Venturini, Julia
Parc, Léna
Nigioni, Ariana
author_facet Messamah, Lina Y.
Bouchy, François
Venturini, Julia
Parc, Léna
Nigioni, Ariana
contents Exoplanet demographic studies rely on large and homogeneous catalogs, yet stellar multiplicity remains incompletely characterised in many planet samples. Misidentified stellar companions can bias both stellar and planetary parameters, leading to ambiguous and incomplete conclusions about planet formation and evolution. We aim to construct a robust and reliable reference catalog of S-type exoplanets for future investigations of planet formation and evolution in multiple-star environments, and to reassess exoplanet demographics by comparing planets hosted by single-stars and binary systems in a statistically consistent framework. We update the PlanetS catalog of transiting exoplanets by systematically identifying gravitationally bound stellar companions using Gaia DR3. Adopting a deliberately conservative classification, we distinguish binary and single-star systems and constructed a matched control sample of single hosts to mitigate selection and observational biases. Using this curated dataset of 860 transiting exoplanets including 133 S-type planets, we performed a comparative demographic analysis of planetary properties as a function of host multiplicity, stellar mass, and binary separation. We find a binary fraction of 19.4% relative to the control sample (15.5% relative to the full single-star sample), consistent with previous estimates but derived from a larger and more homogeneous dataset. Significant demographic differences emerge in the giant planet regime, less affected by observational biases. We find that giant planets in binaries tend to be more massive than their single-star counterparts and to orbit closer to their host stars, making their radius more inflated. In particular, we identify a tentative excess of giant planets orbiting M-dwarfs in binaries with separations < 1000 AU, suggesting a potentially informative regime for future demographic studies.
format Preprint
id arxiv_https___arxiv_org_abs_2605_31523
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Mind the Companion : Demographics of Transiting S-type Exoplanets
Messamah, Lina Y.
Bouchy, François
Venturini, Julia
Parc, Léna
Nigioni, Ariana
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
Exoplanet demographic studies rely on large and homogeneous catalogs, yet stellar multiplicity remains incompletely characterised in many planet samples. Misidentified stellar companions can bias both stellar and planetary parameters, leading to ambiguous and incomplete conclusions about planet formation and evolution. We aim to construct a robust and reliable reference catalog of S-type exoplanets for future investigations of planet formation and evolution in multiple-star environments, and to reassess exoplanet demographics by comparing planets hosted by single-stars and binary systems in a statistically consistent framework. We update the PlanetS catalog of transiting exoplanets by systematically identifying gravitationally bound stellar companions using Gaia DR3. Adopting a deliberately conservative classification, we distinguish binary and single-star systems and constructed a matched control sample of single hosts to mitigate selection and observational biases. Using this curated dataset of 860 transiting exoplanets including 133 S-type planets, we performed a comparative demographic analysis of planetary properties as a function of host multiplicity, stellar mass, and binary separation. We find a binary fraction of 19.4% relative to the control sample (15.5% relative to the full single-star sample), consistent with previous estimates but derived from a larger and more homogeneous dataset. Significant demographic differences emerge in the giant planet regime, less affected by observational biases. We find that giant planets in binaries tend to be more massive than their single-star counterparts and to orbit closer to their host stars, making their radius more inflated. In particular, we identify a tentative excess of giant planets orbiting M-dwarfs in binaries with separations < 1000 AU, suggesting a potentially informative regime for future demographic studies.
title Mind the Companion : Demographics of Transiting S-type Exoplanets
topic Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2605.31523