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arXiv · 2510.20870

pyROX: Rapid Opacity X-sections

Sam de Regt·Siddharth Gandhi·Louis Siebenaler·Darío González Picos
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Abstract

In recent years, significant advances have been made in exoplanet and brown dwarf observations. By using state-of-the-art models, astronomers can determine properties of their atmospheres, such as temperatures, the presence of clouds, or the chemical abundances of molecules and atoms. Accurate and up-to-date opacities are crucial to avoid inconclusive or biased results, but it can be challenging to compute opacity cross-sections from the line lists provided by various online databases. We introduce pyROX, an easy-to-use Python package to calculate molecular and atomic cross-sections. Since pyROX works on CPUs, it can compute a small line list on a regular workstation, but it is also easily parallelised on a cluster for larger line lists. In addition to line opacities, pyROX also supports calculations of collision-induced absorption. Tutorials are provided in the online documentation which explain the configuration parameters and different functionalities of pyROX.

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Sam de Regt, Siddharth Gandhi, Louis Siebenaler, Darío González Picos. 2025-10-23. pyROX: Rapid Opacity X-sections. https://arxiv.org/abs/2510.20870

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