New James Webb Space Telescope observations present a fresh challenge to long-held ideas about the chemistry of planet-forming disks, revealing a surprisingly high concentration of carbon dioxide in regions that may eventually give rise to Earth-like bodies.
Appearing in Astronomy and Astrophysics, the recent research utilized Webb's MIRI instrument, a technology at the heart of many recent astronomical advances, to collect what astronomers found to be anomalous new data.
The paper may suggest a new path forward in identifying strange isotopes detected in meteorites from the birth of our own solar system.
"Unlike most nearby planet-forming disks, where water vapor dominates the inner regions, this disk is surprisingly rich in carbon dioxide," says lead author Jenny Frediani, PhD student at the Department of Astronomy, Stockholm University. "In fact, water is so scarce in this system that it's barely detectable -- a dramatic contrast to what we typically observe."
Stars form from clouds of gas that linger around after a stellar birth. These clouds are not finished with creation at that point; instead, plants form as the loose collections of matter pull together. As typically understood, this means that ice-filled pebbles migrate from chilled edges, closer to their star, sublimating their water.
Human scientific instruments trained on such planet-forming regions pick this up as water vapor signatures emanating from the inner zones. What defies expectations in the new research is the presence of a strong carbon dioxide signature detected by the James Webb Space Telescope, originating from the center of a planet-forming disk rather than the center of the star.
"This challenges current models of disk chemistry and evolution since the high carbon dioxide levels relative to water cannot be easily explained by standard disk evolution processes," Frediani explains.
Adding to the intrigue, the spectrometry results from the James Webb Space Telescope's MIRI instrument identified that the carbon dioxide present was occurring in rare isotopically variant forms. These observations may answer some lingering questions astronomers have regarding the birth of our solar system. Some comets and meteorites, which can be traced back to the beginnings of our solar system, harbor similarly strange isotopic signatures that have long perplexed researchers.
The area of the cosmos that Webb peered into for this study is designated NGC 6357, located approximately 53 trillion kilometers from Earth. Researchers investigating the disk were part of the eXtreme Ultraviolet Environments (XUE) collaboration, a scientific endeavor that brings together professionals to study how intense radiation fields affect the chemistry of such disks.
"It reveals how extreme radiation environments -- common in massive star-forming regions -- can alter the building blocks of planets," said Maria-Claudia Ramirez-Tannus from the Max Planck Institute for Astronomy in Heidelberg and lead of the XUE collaboration. "Since most stars and likely most planets form in such regions, understanding these effects is essential for grasping the diversity of planetary atmospheres and their habitability potential."
Since its launch, the James Webb Space Telescope's MIRI instrument has proven to be a boon for deep space research. Distant objects, such as these dust-filled disks, can now be observed in infrared wavelengths at a level of precision previously unattainable.
By using this instrument to focus on regions of space where planet formation processes are visible, astronomers are gaining new knowledge of the physical and chemical conditions present through direct observations.
The observations are also enabling comparisons to less active regions, allowing astronomers to discern how environmental diversity impacts the birth and evolution of planetary systems across the universe.
The recent paper, "XUE: The CO_2-rich Terrestrial Planet-forming Region of an Externally Irradiated Herbig Disk," appeared in Astronomy and Astrophysics on August 29, 2025.