Observations by the James Webb Space Telescope have revealed carbon dioxide and hydrogen peroxide on the surface of Charon, Pluto's largest moon. This marks the first detection of these compounds, which are frozen as solids, contributing to Charon's known composition that includes water ice, ammonia-bearing compounds, and organic materials.
Charon, with a diameter of about 750 miles (1,200 km), is the largest moon relative to its planet in the solar system, orbiting Pluto at a distance of approximately 12,200 miles (19,640 km). The new findings build on data from NASA's New Horizons spacecraft, which flew by Charon in 2015.
The presence of hydrogen peroxide indicates the moon's surface has undergone significant chemical alterations due to ultraviolet radiation and energetic particles over billions of years. Meanwhile, the carbon dioxide is believed to have originated from the primordial material from which both Charon and Pluto formed around 4.5 billion years ago.
Silvia Protopapa, co-investigator of the New Horizons mission, expressed satisfaction with the confirmation of carbon dioxide and surprise at the unexpected detection of hydrogen peroxide. These discoveries contribute to understanding the processes shaping celestial bodies in our solar system.
Using the Near-Infrared Spectrograph, researchers conducted observations in 2022 and 2023, providing comprehensive coverage of Charon's northern hemisphere. The findings enhance knowledge of ongoing processes affecting Charon's surface and its evolutionary history.