WASHINGTON -

Groundbreaking observations from the James Webb Space Telescope (JWST) are shedding light on the composition and evolution of Charon, Pluto's largest moon and the biggest moon relative to its planet in our solar system.

For the first time, researchers have detected solid-state carbon dioxide and hydrogen peroxide on Charon's surface, expanding the known composition beyond the previously documented water ice, ammonia compounds, and organic materials. Charon spans approximately 750 miles (1,200 km) in diameter, making it a fascinating subject for scientists eager to understand the outer solar system.

Discovered in 1978, Charon is astonishingly about half the diameter of Pluto and one-eighth its mass. Located about 12,200 miles (19,640 km) from Pluto, it orbits in the frigid Kuiper Belt, a realm beyond our solar system's outer planets.

Most of Charon’s surface is gray, but its poles feature reddish-brown areas rich in organic materials, hinting at a dynamic geological history. These new findings build on earlier data collected by NASA’s New Horizons spacecraft during its historic flyby in 2015.

The Webb telescope, launched in 2021, can observe a wider range of wavelengths, enabling these revelations. The presence of hydrogen peroxide indicates that Charon has undergone significant irradiation processes over billions of years, while carbon dioxide is believed to be an original component from its formation roughly 4.5 billion years ago.

Researchers have theorized that hydrogen peroxide formed as a result of water ice on Charon being chemically altered due to relentless UV radiation from the sun and energetic particles from cosmic sources. On the other hand, the carbon dioxide is thought to be buried beneath the surface and has been exposed through impacts, likely being part of the primordial material that formed both Charon and Pluto. Scientists were previously puzzled by the absence of carbon dioxide in earlier studies.

Silvia Protopapa, assistant director of the department of space studies at the Southwest Research Institute in Boulder, Colorado, expressed her excitement: “The detection of carbon dioxide was a satisfying confirmation of our expectations, while the discovery of hydrogen peroxide was a revelation I honestly did not anticipate,” she noted. Her team’s findings were published in the journal Nature Communications.

These crucial observations reveal that Charon is an essential piece of a larger astronomical puzzle, helping scientists unravel the deeper narratives of various celestial bodies within our solar system.

The researchers harnessed the Near-Infrared Spectrograph on Webb for a series of observations between 2022 and 2023, achieving complete coverage of Charon's northern hemisphere. "These groundbreaking observations add carbon dioxide and hydrogen peroxide to the known inventory of Charon’s surface components," co-author Ian Wong explained. "They give us vital insights into the ongoing processes of irradiation and impact-driven resurfacing."

Stay tuned as these findings pave the way for further exploration and understanding of our cosmic neighborhood!