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Rapoc: the Rosseland and Planck opacity converter. A user-friendly and fast opacity program for Python

Mugnai, Lorenzo V. ORCID: and Modirrousta-Galian, Darius 2021. Rapoc: the Rosseland and Planck opacity converter. A user-friendly and fast opacity program for Python. Presented at: European Planetary Science Congress 2021, Online, 13–24 Sep 2021. EPSC Abstracts. , vol.18 EPSC2021-108. 10.5194/epsc2021-108

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We present a novel code that converts the widely-used wavelength-dependent opacities of gaseous species into Rosseland and Planck mean opacities (RPMs). RAPOC (Rosseland and Planck Opacity Converter) is a straightforward and efficient Python code that makes use of ExoMol and DACE data as well as any other user-defined data, provided that it is within the correct format. Furthermore, RAPOC has the useful ability of rapidly interpolating between discrete data points, therefore allowing for a complete incorporation in atmospheric models. Whereas RPMs should not be used as a replacement for more rigorous opacity analyses, they have certain benefits. For example, RPMs allow one to use Grey or semi-Grey models when analysing gaseous environments; which are simpler, have exact solutions, and can be used as benchmarks for more rigorous approaches. By incorporating the pressure and temperature dependence of RPMs, RAPOC provides a more complex treatment of the mean opacities than what is sometimes used within the literature, notably assuming constant values or adopting simple analytic formulations. We report examples of RAPOC opacities that are incorporated into a semi-Grey model to produce the temperature profile of HD 209458 b that is then compared to the realisations of the more rigorous POSEIDON code. The RAPOC code will provide the exoplanetary community a new tool for atmospheric modelling. For a quick installation in one's machinery, the “pip install rapoc” command can be used.

Item Type: Conference or Workshop Item (Paper)
Status: Published
Schools: Physics and Astronomy
Last Modified: 05 Jun 2023 10:52

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