A look into the universe with the James Webb Space Telescope reveals surprises: rocky planets could form even under the harshest conditions
An international team of astronomers has used NASA’s James Webb Space Telescope to observe water and other molecules in the highly irradiated, rocky, planet-forming inner regions of a disk in one of the most extreme environments in our galaxy for the first time. This discovery is part of the initial results of the James Webb Telescope’s eXtreme Ultraviolet Environments (XUE) program, which focuses on characterizing planet-forming disks in massive star-forming regions.
The XUE program focuses on 15 disks in three areas of the Lobster Nebula (also known as NGC 6357), a large emission nebula located about 5,500 light-years from Earth in the constellation Scorpius. This nebula is one of the youngest and closest massive star-forming complexes and hosts some of the most massive stars in our galaxy.

Abundant water, CO, 12CO2, HCN, and C2H2 were detected in the few inner AUs of XUE 1, a highly irradiated disk in NGC 6357
Astronomers want to characterize the physical properties and chemical composition of the rocky planet-forming regions of the disks in the Lobster Nebula using the medium-resolution spectrometer on Webb’s Mid-Infrared Instrument (MIRI). This first result focuses on the protoplanetary disk called XUE 1, located in the star cluster Pismis 24.
Despite being constantly exposed to large amounts of ultraviolet radiation, the team discovered in this extreme environment a number of molecules that are the building blocks of rocky planets. “The inner disk around XUE 1 is strikingly similar to those in nearby star-forming regions,” commented Rens Waters of Radboud University in the Netherlands. Water and other molecules such as carbon monoxide, carbon dioxide, hydrogen cyanide and acetylene were detected, although the emission detected was weaker than some models had predicted.
These results are encouraging for rocky planet formation because conditions in the inner disk are similar to those in well-studied disks in nearby star-forming regions where only low-mass stars form. This suggests that rocky planets can form in a much wider range of environments than previously thought.
REFERENCES
XUE: Molecular Inventory in the Inner Region of an Extremely Irradiated Protoplanetary Disk, published in the Astrophysical Journal