Publications

This page presents a curated collection of research articles central to the study of hycean worlds from our team.

These papers cover a wide range of topics including theoretical frameworks, observational data, atmospheric modeling, and biosignature prospects.

Organized into thematic sections, this list is intended as a starting point for researchers, students, and enthusiasts seeking to explore the scientific developments and methodologies that underpin the hycean paradigm.

Key background readings

• Habitability and Biosignatures, N. Madhusudhan, 2025
• The Hycean Paradigm in the Search for Life Elsewhere, N. Madhusudhan, 2024
• Habitability and Biosignatures of Hycean Worlds, N. Madhusudhan, A. Piette, & S. Constantinou, 2021
• The Interior and Atmosphere of the Habitable-zone Exoplanet K2-18b, N. Madhusudhan, M. C. Nixon, L. Welbanks, et al. 2020

Theoretical foundations of hycean worlds

• A new convection scheme for GCMs for temperate sub-Neptunes, E. Barrier & N. Madhusudhan, 2025 
• Prospects for biological evolution on Hycean worlds, E.G., Mitchell & N. Madhusudhan, 2025
• Considerations for Photochemical Modeling of Possible Hycean Worlds, Cooke GJ & Madhusudhan N. 2024 
• On the ocean conditions of Hycean worlds, Rigby F & Madhusudhan N, 2024
• Toward a Self-consistent Evaluation of Gas Dwarf Scenarios for Temperate Sub-Neptunes, Rigby F.E., Pica-Ciamarra L., Holmberg M., Madhusudhan N., Constantinou S., et al., 2024, 
• Chemical conditions on Hycean worlds, Madhusudhan, N., Moses, J. I., Rigby, F., & Barrier, E. 2023 
• Habitability and Biosignatures of Hycean Worlds, N. Madhusudhan, A. Piette, & S. Constantinou, 2021
• How deep is the ocean? Exploring the phase structure of water-rich sub-Neptunes, M. C. Nixon, N. Madhusudhan, 2021
• The Interior and Atmosphere of the Habitable-zone Exoplanet K2-18b, N. Madhusudhan, M. C. Nixon, L. Welbanks, et al. 2020
• On the Temperature Profiles and Emission Spectra of Mini-Neptune Atmospheres, A. A. A. Piette, N. Madhusudhan, 2020

Observations of hycean candidates

• Characterising M dwarf host stars of two candidate Hycean worlds, L. Sairam & N. Madhusudhan, 2025
• High-resolution Spectroscopic Reconnaissance of a Temperate Sub-Neptune, S. Cabot, N. Madhusudhan, et al. 2024 
• Possible Hycean conditions in the sub-Neptune TOI-270 d, M. Holmberg & N. Madhusudhan, 2024 
• Carbon-bearing molecules in a possible hycean atmosphere, N. Madhusudhan, S., Sarkar, S., Constantinou, M., Holmberg, A.A.A., Piette, & J.I., Moses, 2023 
• Hubble Space Telescope Transmission Spectroscopy for the Temperate Sub-Neptune TOI-270 d: A Possible Hydrogen-rich Atmosphere Containing Water Vapor T. Mikal-Evans, N. Madhusudhan,. et al. 2023

Observation and retrieval techniques

• Feasibility of High-resolution Transmission Spectroscopy for Low-velocity Exoplanets, C. J. Cheverall, N. Madhsudhan, 2024
• VIRA: an exoplanet atmospheric retrieval framework for JWST transmission spectroscopy, S. Constantinou & N. Madhusudhan, 2024
• Exoplanet transit spectroscopy with JWST NIRSpec: diagnostics and homogeneous case study of WASP-39 b, S. Sarkar, N. Madhusudhan, S. Constantinou, M. Holmberg, 2024
• Robustness measures for molecular detections using high-resolution transmission spectroscopy of exoplanets, C. J. Cheverall, N. Madhusudhan, M. Holmberg, 2023
• Early Insights for Atmospheric Retrievals of Exoplanets Using JWST Transit Spectroscopy, S. Constantinou, N. Madhusudhan, and S. Gandhi, 2023
• Exoplanet spectroscopy with JWST NIRISS: diagnostics and case studies, M. Holmberg & N. Madhusudhan, 2023
• Characterizing atmospheres of cloudy temperate mini-neptunes with JWST, S. Constantinou & N. Madhusudhan, 2022
• Aura-3D: A Three-dimensional Atmospheric Retrieval Framework for Exoplanet Transmission Spectra, M. C. Nixon, N. Madhusudhan, 2022
• HyDRo: atmospheric retrieval of rocky exoplanets in thermal emission, A. Piette, N. Madhusudhan, A. M. Mandell, 2022
• JexoSim 2.0: end-to-end JWST simulator for exoplanet spectroscopy – implementation and case studies, S. Sarkar, N. Madhusudhan, 2021
• On Atmospheric Retrievals of Exoplanets with Inhomogeneous Terminators, L. Welbanks, N. Madhusudhan, 2022 
• Aurora: A Generalized Retrieval Framework for Exoplanetary Transmission Spectra, L. Welbanks & N. Madhusudhan, 2021
• Assessment of supervised machine learning for atmospheric retrieval of exoplanets, M. C. Nixon & N. Madhusudhan, 2020 
• Considerations for atmospheric retrieval of high-precision brown dwarf spectra, A. A. A. Piette, N. Madhusudhan, 2020