An expanded grid of chemical equilibrium abundance for petitRADTRANS

This dataset provides an updated grid of chemical equilibrium (CEQ) abundances for use with petitRADTRANS (Mollière et al. 2019; Nasedkin et al. 2024), an open-source package for computing exoplanet and brown dwarf spectra and conducting atmospheric retrievals.

Compared to the default CEQ grid included in petitRADTRANS version 2 and version 3, this new grid extends to higher temperatures and incorporates additional atomic and molecular species. Specifically, the updated grid spans [40 K, 6000 K] in temperature, [10^-8, 10^3] bar in pressure, [-2, +3] dex in metallicity [M/H], and [0.1, 1.6] in the carbon-to-oxygen ratios (C/O).

How to implement this new grid? Locate the abundance_files/ folder under the pRT_input_data/ folder created when installing petitRADTRANS, and then simply replace it with the updated abundance_files/ folder provided in this repository.

This dataset is presented in the paper ``ELemental abundances of Planets and brown dwarfs Imaged around Stars (ELPIS): II. The Jupiter-like Inhomogeneous Atmosphere of the First Directly Imaged Planetary-Mass Companion 2MASS 1207 b'' (Zhang et al. 2025) accepted for publication in the Astronomical Journal. If you use this updated CEQ grid in your work, please cite both the paper and this associated Zenodo repository.