JWST spectra reveal unidentified absorber on Titan and Pluto surfaces inconsistent with known tholins or ices

The Paris group cross-referenced the feature against laboratory spectra of nitrogen-methane photochemistry products and New Horizons surface maps. No single compound reproduced the narrow Titan dip or the broader Pluto counterpart, even after testing grain-size variations and binary mixtures. This points to a complex, possibly polymerised surface deposit formed by atmospheric haze sedimentation on both bodies despite their 100 K temperature difference. The finding exposes gaps in current photochemical networks that assume tholin optical properties dominate surface reflectance beyond 2 µm. Cassini VIMS and New Horizons LEISA datasets had hinted at similar unexplained slopes but lacked the spectral resolution now provided by JWST. Dragonfly’s in-situ mass spectrometry in 2034 remains the only direct test capable of distinguishing between a novel macromolecule and an unrecognised ice mixture.