ESA released a new James Webb Space Telescope image of the Westerlund 2 cluster at the end of 2025, offering far greater detail than Hubble’s celebrated 2015 photograph. Using NIRCam and MIRI, Webb reveals hundreds of additional faint stars and intricate gas filaments in the nebula, located about 20,000 light-years away and spanning 6–13 light-years. The data also include a brown dwarf census down to roughly ten times Jupiter’s mass, enabling studies of disk evolution and planet formation in dense stellar environments.
Webb Unveils a Deeper View of Westerlund 2 — A Decade After Hubble
Astronomers are studying the hundreds of young, brown dwarf stars inside the stellar nursery.
In 2015, NASA celebrated the Hubble Space Telescope’s 25th year in orbit by releasing a vivid image of the stellar cluster Westerlund 2 in the constellation Carina. A decade later, the James Webb Space Telescope (JWST) has delivered a far more detailed portrait, and the European Space Agency (ESA) closed out 2025 by publishing an even deeper Webb image to showcase the telescope’s technological advances.
Sharper, Deeper Imaging
The billowing nebula lies roughly 20,000 light-years from Earth and spans an estimated 6 to 13 light-years across. JWST captured the scene using its Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI), revealing hundreds of faint stars and intricate gas filaments that Hubble could not resolve. To highlight these differences, ESA also published an interactive slider that lets viewers compare the Hubble and Webb images side by side.
A Dynamic Stellar Nursery
Young, massive stars in Westerlund 2 emit intense radiation and stellar winds that twist, erode, and sculpt the surrounding clouds of gas and dust. The Webb image shows luminous central stars as well as hundreds of tiny points of light — many of them younger, lower-mass members — embedded in thick red and orange plumes and finer blue and pink filaments, painting the picture of an actively forming cluster.
Scientific Payoff
Beyond its visual power, Webb’s new observations include a census of the nebula’s brown dwarf population, detecting objects down to about ten times the mass of Jupiter. These measurements allow astronomers to study how circumstellar disks form and evolve in dense, radiation-rich environments and to investigate how planets might form and survive near massive, energetic stars.
Why It Matters
By resolving fainter stars and substellar objects in crowded regions, Webb is reshaping our view of star and planet formation in extreme environments. The Westerlund 2 images are a clear demonstration of how next-generation infrared observatories extend and deepen discoveries first hinted at by Hubble.
