The Sonora Substellar Atmosphere Models. V: A Correction to the Disequilibrium Abundance of CO$_2$ for Sonora Elf Owl

TL;DR

This paper presents an updated version of the Sonora Elf Owl atmospheric model grid, correcting CO$_2$ quenching estimates and removing PH$_3$ from spectra to improve accuracy for interpreting substellar observations.

Contribution

The authors provide a corrected and improved version of the Sonora Elf Owl model grid, addressing previous inaccuracies in CO$_2$ abundance and spectral contributions.

Findings

Corrected CO$_2$ abundances in the model grid.

Removed excess PH$_3$ spectral features.

Updated spectra available on Zenodo.

Abstract

To aid the interpretation of observations of substellar atmospheres, Mukherjee et al. (2024) created the Sonora Elf Owl grid of model atmospheres, simulations that accounted for disequilibrium quench chemistry. However, Sonora Elf Owl did not accurately estimate CO$_2$ quenching because the models quenched the gas with respect to the full atmosphere equilibrium, but CO$_2$ should have instead been quenched with respect to the disequilibrium (i.e., quenched) abundance of CO. As a result, Sonora Elf Owl under-predicted the CO$_2$ abundance by several order of magnitude in some instances, an amount that JWST is sensitive to. Here, we release version two of the Sonora Elf Owl grid which has corrected CO$_2$ concentrations. Additionally, in version two we remove PH$_3$ as a spectral contributor since our spectra consistently contained too much PH$_3$ absorption. The new spectra can be found as an update to the original Zenodo postings.