NASA’s Webb Telescope Detects Carbon-Rich Moon-Forming Disk Around Distant Exoplanet

NASA’s James Webb Space Telescope has captured the first direct measurements of a potential moon-forming disk around the exoplanet CT Cha b, located 625 light-years from Earth. Although no moons have been observed, the carbon-rich circumplanetary disk may serve as a construction site for future satellites.

The planet orbits a young star only 2 million years old. Webb’s observations reveal that the planet’s disk is separate from the star’s larger circumstellar disk, lying 46 billion miles apart. Studying such disks is key to understanding how planets and moons form, and offers insight into processes that shaped our own solar system.

Using Webb’s MIRI instrument, researchers identified seven carbon-bearing molecules in the disk, including acetylene and benzene. The carbon-rich chemistry contrasts with the host star’s disk, which contains water but lacks carbon, highlighting rapid chemical evolution in just 2 million years.

“This allows us to study the chemistry of a planet and its potential moons as they form,” said Sierra Grant of the Carnegie Institution for Science. Co-lead Gabriele Cugno added, “Webb lets us witness the drama of moon formation and investigate the ingredients and processes at play.”

The discovery provides a modern parallel to the circumplanetary disk that likely birthed Jupiter’s Galilean moons. The team plans to survey similar systems with Webb over the next year to explore the diversity of disks around young planets.

The James Webb Space Telescope, led by NASA in collaboration with ESA and CSA, continues to advance our understanding of planetary formation, distant worlds, and the origins of our universe.