On October 1, 2024, astronomers using NASA's James Webb Space Telescope (JWST) identified carbon dioxide and hydrogen peroxide on the surface of Charon, Pluto's largest moon. This groundbreaking discovery was made by a research team from the Southwest Research Institute in Colorado and published in the journal Nature Communications.
Despite previous studies since Charon's discovery in 1978, the presence of these molecules remained undetected until now. The JWST's Near Infrared Spectrograph (NIRSpec) allowed scientists to fill gaps in knowledge regarding Charon's composition.
Lead researcher Silvia Protopapa stated that the findings reveal evidence of Charon's formation through the detected carbon dioxide and indicate irradiation processes via the presence of hydrogen peroxide. Charon, measuring approximately 1,207 kilometers in diameter, is located in the Kuiper Belt, an area populated with icy debris, comets, and dwarf planets.
While the presence of carbon dioxide was anticipated based on the protoplanetary disk from which the Pluto system formed, the detection of hydrogen peroxide was unexpected. This compound, also found on Jupiter's moon Europa, suggests that Charon's water-ice-rich surface is actively altered by solar ultraviolet light, energetic particles from solar wind, and galactic cosmic rays.
The JWST will continue to observe Charon to address unexamined spectral gaps, potentially expanding the moon's chemical inventory and uncovering additional processes at play.