JWST detects unknown compound on Pluto and Titan

The James Webb Space Telescope (JWST) has detected an unidentified chemical signature on both Pluto and Saturn's moon Titan, baffling astronomers. The absorption band at 5.113 micrometers does not match any known compound in spectral databases, suggesting a mysterious molecule or mixture never before characterized Source: Wired; Gizmodo.

The discovery

Researchers used JWST's spectroscopy to analyze the surfaces of Pluto and Titan, two nitrogen- and methane-rich worlds with very different conditions. The same spectral feature appeared in observations from two different JWST instruments, ruling out instrument error. The study, accepted for publication in Astronomy & Astrophysics, notes that the absorption on Pluto is about three times thicker than on Titan, possibly due to differences in the physical state of the unknown compound Source: Gizmodo.

Possible explanations

• The team examined spectra of known ices and organics like acetylene, benzene, ketene, and allenes, but none exactly matched Source: Wired.
• The signal may come from a known compound in an unstudied physical state or mixture, or from a material whose chemistry hasn't been characterized Source: Wired.
• “We have a few candidates, but it will not be a simple compound,” said lead author Bruno Bézard of the Paris Observatory Source: Gizmodo.

Next steps

The researchers have secured additional JWST time for follow-up. In the mid-2030s, NASA's Dragonfly mission will reach Titan, potentially providing surface data, though it lacks onboard infrared spectroscopy to directly detect this feature Source: Gizmodo.