Left: atmospheric composition for a planet with 0.1% soot and variable mass. These models have no additional water added beyond the water that might form via the baseline soot composition. Right: atmospheric composition for a 3 M _⊕ planet with variable soot (and water) content. 0.0% H₂O refers to the baseline model where water might form from hydrogen provided by soot and 1.0% water refers to a model with an addition 1 wt% of water included beyond what is provided by soot. In each case, four temperatures are shown that effectively relate to the semimajor axis of the planet’s orbit. We note that these compositions are all at 1 mbar, which is approximately the transmission spectroscopy photosphere. Other species (such as H₂S) are included in the calculation, some with abundances high enough to appear in transmission spectra. Here only those with abundances in excess of 0.1% are shown.