Probing Exoplanetary Chemistry with Ariel: Scientific Priorities and Observational Strategies
Abstract
Over the past two decades, increasingly precise observations have revealed that exoplanet atmospheres are chemically diverse and often far from equilibrium, with processes such as vertical mixing, photochemistry, and atmospheric circulation producing significant departures from thermochemical expectations. As large surveys across a wide range of planets begin to uncover population-level chemical trends, a coherent interpretation of these patterns remains elusive, particularly for gas giants and Neptune-like planets where disequilibrium processes likely dominate. The ESA Ariel mission will provide the first homogeneous, statistically significant atmospheric dataset for nearly a thousand exoplanets, offering an unprecedented opportunity to investigate the origins of chemical diversity across planetary populations. This white paper highlights central scientific questions for understanding atmospheric chemistry and recognized as priorities for the community. These questions span the mechanisms driving disequilibrium chemistry, the role of sulfur- and phosphorus-bearing species, the influence of stellar activity, the formation of haze precursors, and the chemical evolution of atmospheres around stars of different ages and types. Because these topics connect chemistry, physics, and planetary evolution, they form the core focus of the Ariel Chemistry Working Group, which synthesizes current knowledge and identifies the diagnostics best addressed by Ariel's spectral capabilities. For each theme, we outline observational strategies and representative targets already included in the Mission Candidate Sample, illustrating Ariel's ability to address these questions. By linking large-scale observations to predictive atmospheric models, this work supports refinement of Ariel's target selection and enables population-level studies that will transform our understanding of planetary atmospheres.
Versions
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BibTeX
@misc{venot2026probing,
title = {{Probing Exoplanetary Chemistry with Ariel: Scientific Priorities and Observational Strategies}},
author = {Olivia Venot and Yamila Miguel and Robin Baeyens and Stefano Bellotti and Giuseppe Cassone and Quentin Changeat and Ryan Cloutier and Athena Coustenis and Dwaipayan Dubey and Billy Edwards and Kaustubh Hakim and Eric Hébrard and Christiane Helling and Helgi Rafn Hrodmarsson and Leoni Janssen and Adam Yassin Jaziri and Gaia Lacedelli and Panayotis Lavvas and Jorge Lillo-Box and Amy Louca and Adrien Masson and Zita Martins and Karan Molaverdikhani and Benjamín Montesinos and Harrison Nicholls and Enric Palle and Paul Rimmer and Donna Rodgers-Lee and Jonathan Tennyson and Shang-Min Tsai and Roméo Veillet and Sergey N. Yurchenko and Maria Zamyatina},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.27622},
eprint = {2609.27622},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.27622},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Probing Exoplanetary Chemistry with Ariel: Scientific Priorities and Observational Strategies
AU - Olivia Venot
AU - Yamila Miguel
AU - Robin Baeyens
AU - Stefano Bellotti
AU - Giuseppe Cassone
AU - Quentin Changeat
AU - Ryan Cloutier
AU - Athena Coustenis
AU - Dwaipayan Dubey
AU - Billy Edwards
AU - Kaustubh Hakim
AU - Eric Hébrard
AU - Christiane Helling
AU - Helgi Rafn Hrodmarsson
AU - Leoni Janssen
AU - Adam Yassin Jaziri
AU - Gaia Lacedelli
AU - Panayotis Lavvas
AU - Jorge Lillo-Box
AU - Amy Louca
AU - Adrien Masson
AU - Zita Martins
AU - Karan Molaverdikhani
AU - Benjamín Montesinos
AU - Harrison Nicholls
AU - Enric Palle
AU - Paul Rimmer
AU - Donna Rodgers-Lee
AU - Jonathan Tennyson
AU - Shang-Min Tsai
AU - Roméo Veillet
AU - Sergey N. Yurchenko
AU - Maria Zamyatina
PY - 2026
DA - 2026/09/23
PB - arXiv
DO - 10.48550/arxiv.2609.27622
UR - https://arxiv.org/abs/2609.27622
AB - Over the past two decades, increasingly precise observations have revealed that exoplanet atmospheres are chemically diverse and often far from equilibrium, with processes such as vertical mixing, photochemistry, and atmospheric circulation producing significant departures from thermochemical expectations. As large surveys across a wide range of planets begin to uncover population-level chemical trends, a coherent interpretation of these patterns remains elusive, particularly for gas giants and Neptune-like planets where disequilibrium processes likely dominate. The ESA Ariel mission will provide the first homogeneous, statistically significant atmospheric dataset for nearly a thousand exoplanets, offering an unprecedented opportunity to investigate the origins of chemical diversity across planetary populations. This white paper highlights central scientific questions for understanding atmospheric chemistry and recognized as priorities for the community. These questions span the mechanisms driving disequilibrium chemistry, the role of sulfur- and phosphorus-bearing species, the influence of stellar activity, the formation of haze precursors, and the chemical evolution of atmospheres around stars of different ages and types. Because these topics connect chemistry, physics, and planetary evolution, they form the core focus of the Ariel Chemistry Working Group, which synthesizes current knowledge and identifies the diagnostics best addressed by Ariel's spectral capabilities. For each theme, we outline observational strategies and representative targets already included in the Mission Candidate Sample, illustrating Ariel's ability to address these questions. By linking large-scale observations to predictive atmospheric models, this work supports refinement of Ariel's target selection and enables population-level studies that will transform our understanding of planetary atmospheres.
ER -