Astronomers using the James Webb Space Telescope have found evidence of a disk of planet-building material around an object with an estimated mass of just twice Jupiter’s. The object, classified as a brown dwarf, could offer an unusually small setting for planet formation—although the observations have not detected planets around it.
NASA featured the finding on September 15, 2026, with a newly released panorama of IC 348, a star-forming region about 1,000 light-years from Earth in the constellation Perseus. The image shows a much broader scene of stellar birth, including young stars sending jets of material into surrounding clouds. The research behind the brown dwarf discovery was first made publicly available on June 10, 2025.
What is a brown dwarf?
Brown dwarfs occupy an uncertain boundary between stars and planets. Like stars, they are thought to form when clouds of gas collapse under their own gravity. Unlike stars, however, they do not gain enough mass for their interiors to sustain the fusion of ordinary hydrogen—the process that powers the Sun. Some have masses comparable to giant planets.
That makes an object’s origin important, not simply how much it weighs. A lightweight body that formed independently from a collapsing cloud may be described as a brown dwarf, even when its mass resembles a planet’s. Researchers studying IC 348 have favored a star-like origin for its tiny free-floating objects, while acknowledging that an alternative—planets expelled from planetary systems—cannot be entirely ruled out.
The comparison with Jupiter concerns mass, or the amount of matter the object contains, rather than its diameter.
Why a disk could matter for planet formation
Planets are thought to develop in rotating disks of gas and dust surrounding young stars. Within these disks, small dust particles can collide and stick together, gradually building larger bodies. Further growth and gravitational interactions can eventually produce planets. Our own solar system is thought to have begun through this broad process.
A disk is therefore more than material left over from an object’s birth: it can provide the ingredients for worlds that orbit it. The question raised by Webb’s observations is whether that process can operate around a central body with only a few times Jupiter’s mass, rather than around a star. NASA describes small planets forming around the newly identified brown dwarf as a possibility, not an established finding.
What Webb actually detected
The study, by Kevin Luhman of Pennsylvania State University and Catarina Alves de Oliveira of the European Space Agency, found excess infrared emission around two newly identified brown dwarfs, with estimated masses of roughly two and ten times Jupiter’s. In other words, the objects gave off more light at certain infrared wavelengths than expected from their atmospheres alone. The researchers interpreted that additional emission as evidence of surrounding disks.
This was not a photograph of individual planets taking shape. The evidence comes from measurements of the objects’ light, and it does not establish whether either disk has already produced smaller orbiting bodies.
Why astronomers searched this stellar nursery
IC 348 is a useful place to look because its cluster is only about five million years old. Young brown dwarfs still retain heat from their formation, making them relatively bright in infrared light and easier to detect than older, cooler objects.
The team used Webb’s Near-Infrared Camera in 2024 to select promising targets based on brightness and color. Follow-up observations in 2025 used its Near-Infrared Spectrograph, which separates light into wavelengths so researchers can examine the objects in greater detail.
How certain is the two-Jupiter estimate?
The researchers inferred the brown dwarf’s mass by comparing its estimated total light output with models of how young objects evolve. They did not weigh it directly through measurements of an orbit. The study cautions that these model-based estimates can have significant errors, so “twice Jupiter’s mass” should be understood as approximate.
The central distinction remains between finding potential ingredients and finding planets. Webb has supplied evidence for a disk around an exceptionally lightweight object; whether that material develops into a planetary system is still unanswered.
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