PICASO 4.0: Correlated-k coefficients for H2-He atmospheres; 196 spectral windows and 1460 pressure-temperature points

Pre-weighted correlated-K tables (method=preweighted): Section 2.1.4 of Mukherjee et al., 2023 details our ``double-Gauss'' method for computing correlated-k tables (see Eqn. 25). In Mukherjee et al., 2023 we previously did not have an open source pipeline to do these calculations. As part of PICASO 4.0 this is now included in pure Python in opacity_factory.compute_ck_molecular. To compute our pre-weighted K-tables on a 196 wavelength grid, we use the pre-computed chemistry grid described in Mang et al. 2026 in Section 2.2.1, which makes our table primarily a function of metallicity and carbon-to-oxygen ratio. We include the chemistry and opacity sources of everything in Table 1 of Mang et al (see screen grab below). Of note, we create one complete table with TiO and VO and another table without. We recommend downloading all the files. Our H5 file structure includes: 'chemistry_file' : defines the chemistry file used 'ck_molecules': describes the opacity sources used 'pressure_bar' : define the pressure grid 'temperature_K': defines the temperature grid 'abunds': includes the full abundances used for weighting in matrix form 'abunds_map': includes the list of species for ordering to use with abunds 'kcoeffs': [npressure, ntemperature, nwave, ngauss ] cm2 They can easily be read with the picaso function `picaso.opacity_factory.get_ck_tables`