Pyrat Bay¶
Python Radiative Transfer in a Bayesian framework
- Author:
Patricio Cubillos & Jasmina Blecic
- Contact:
- Organizations:
- Web site:
- Date:
Oct 14, 2026
Features¶
Pyrat Bay is an efficient, user-friendly Python tool to compute
radiative-transfer spectra, and fit exoplanet atmospheric properties.
This package offers:
Transmission, eclipse, or emission spectral synthesis of exoplanet atmospheres.
Forward-model, radiative-equilibrium, or (multinest) retrieval calculations.
Radiative-transfer calculations include opacity sources from:
Line-by-line molecular absorption
Collision-induced absorption
Rayleigh scattering absorption
Na and K alkali resonant lines
Gray and (soon) Mie aerosol opacities
Bayesian (Nested sampling) posterior sampling of atmospheric parameters:
Molecular abundances (free-, equilibrium-, or hybrid chemistry)
Temperature profiles
Pressure-radius
Rayleigh and cloud properties
Transit light source effect (TLS)
Offsets between observing instruments
Error scaling for observations
Isotopic-ratio fitting
Contributors¶
Patricio Cubillos (IWF, Austria) patricio.cubillos[at]oeaw.ac.at
Jasmina Blecic (NYU, Abu Dhabi)
Be Kind¶
- If you found
Pyrat Bayuseful for your research, please cite this article: Cubillos & Blecic (2021): The Pyrat Bay Framework for Exoplanet Atmospheric Modeling: A Population Study of Hubble/WFC3 Transmission Spectra, MNRAS, 505, 2675.
- For the update including Multinest retrievals, radiative equilibrium, TLS, isotopic ratios, and/or direct-imaging spectra:
Cubillos et al. (2026): PYRAT BAY 2.0: an upgraded framework for exoplanet atmosphere modelling in the JWST era, MNRAS, 551, 1526.
Please prefer to channel your feedback or inquiries through the Github issue tracker: https://github.com/pcubillos/pyratbay, or alternatively through this email: patricio.cubillos[at]oeaw.ac.at.
Pyrat Bay is open-source software under the GNU GPL v2 license (see
License) and is compatible with Python>=3.10.