Using the zero-dimensional LTE SLAB-models that are part of ProDiMo, Arabhavi et al. (2024, SCIENCE-paper) have analysed the mid-infrared JWST/MIRI spectrum of the protoplanetary disk around ISO-ChaI 147, a young 0.11-solar-mass M-type star, finding that its spectrum is dominated by small hydrocarbon molecules, which indicates a high carbon/oxygen ratio in the inner disk gas. 

The following molecules, including ethane and benzene, were detected: CH4, C2H2, 13CCH2, C2H4, C2H6, CO2, 13CO2, HCN, HC13N, CH3, but no H2O and no CO.  The column densities derived for some of these hydrocarbon molecules are very large,  > 10²² cm⁻², indicating that the observations probe deep into the disk, which requires the dust to be either absent or very transparent in these regions.  The emitting areas fitted to the spectrum correspond to a tiny central region around the star between about 0.04 and 0.09 au. The non-detection of CO suggests that the gas in this region is very poor in oxygen.