Astronomers utilizing the NASA/ESA/CSA James Webb Space Telescope have identified a carbon-rich disk encircling CT Cha B, a massive exoplanet located approximately 620 light years from Earth in the Chamaeleon constellation. This discovery offers the first direct insights into the chemical and physical characteristics of the gas giant and the materials that might contribute to its potential lunar system.
Artistic rendering of dust and gas discs surrounding a young exoplanet CT Cha b. Image credits: NASA/ESA/CSA/STSCI/G. CUGNO, University of Zurich & NCCR Planets/S. Grant, Carnegie Institution for Science/J. Olmsted, Stsci/L. Hustak, Stsci.
CT CHA, also referred to as PDS 44 and TIC 454259409, is merely 2 million years old and continues to accumulate materials for its formation.
However, the disks identified by Webb are independent of the larger accretion disks surrounding the central star.
“We can observe signs of disks around companion celestial bodies and explore their chemistry for the first time,” remarks Dr. Sierra Grant, an astronomer at the Carnegie Institution for Science.
“We are not merely observing the moon’s formation; we are witnessing the planet’s formation as well.”
“We are investigating the materials involved in forming planets and moons,” added Dr. Gabriele Kuno, an astronomer from the University of Zurich and the National Center for Capacity for Research Planets.
Infrared observations of CT CHA B have been captured by Webb’s MIRI (Mid-Infrared Instrument), which employs a medium-resolution spectrometer.
An initial examination of Webb’s archived data revealed evidence of molecules in the surrounding disk, prompting deeper analysis of the data.
The planet’s faint signal is obscured by the glare of its host star, requiring astronomers to utilize high-contrast techniques to separate the star’s light from that of the planet.
“We detected molecules in the planet’s vicinity, indicating there was something significant to delve into within the data, which took us a year of dedicated effort. It truly required a lot of patience,” Dr. Grant stated.
Ultimately, researchers identified seven carbon-containing molecules within the disk, including acetylene (C2H2) and benzene (C6H6).
This carbon-rich chemistry contrasts sharply with that found in the disks around the host star, where water was detected alongside carbon.
The disparity between the two disks suggests rapid chemical evolution occurring within just 2 million years.
“We aim to better understand how our solar system formed its moons. This necessitates examining other systems that are still in the process of development. We are striving to comprehend all the underlying mechanisms,” Dr. Cugno explained.
“What do these moons resemble? What are their components? What physical processes are in action, and what are the associated timescales?”
“Webb is capturing the narrative of moon formation, enabling us to explore these questions observationally for the very first time.”
The survey results were published today in the Astrophysical Journal Letters.
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Gabriele Cugno & Sierra L. Grant. 2025. A carbon-rich disk surrounding the planetary mass ally. ApJL 991, L46; doi: 10.3847/2041-8213/ae0290
Source: www.sci.news
