Unidentified Compound Absorbs Light on Titan and Pluto Surfaces

A narrow band of light is absorbed by an unidentified compound on Titan’s surface, and the same wavelengths appear with a broader spread on Pluto, according to observations reported by @NewScientist. Bruno Bézard at the Paris Observatory and colleagues identified the feature in James Webb Space Telescope data.

Titan’s thick atmosphere makes surface study difficult, and the compound’s identity may clarify the chemistry occurring there.

Both worlds have atmospheres composed mostly of nitrogen and methane. Haze particles produced in those atmospheres can snow down and accumulate on the surface, Bézard said, and that process is probably how the mystery compound forms. The spectral feature does not match any known compounds in Titan’s atmosphere or candidate ices tested in laboratory spectra.

A few near-matching compounds were identified that could fit if modified or mixed with other molecules. Pluto’s atmosphere is about 15,000 times less dense than Titan’s, yet the shared chemistry persists despite the temperature and pressure differences. Grain-size variations may account for the difference in how the spectral feature appears on each body, Bézard said.

“We have a few candidates, but it will not be a simple compound,” Bézard said. ” Additional JWST data have already been obtained to map the substance’s location on Titan’s surface. Laboratory experiments are under way to test whether the near-match compounds can reproduce the observed spectral feature.

NASA’s Dragonfly spacecraft is scheduled to launch in 2028 and land on Titan in 2034. Titan’s surface was imaged in ultraviolet and infrared wavelengths by the Cassini probe in 2004. 13350.