New research from the University of St Andrews has found that giant free-floating planets, which are not in orbit around a star but instead drift in space, may form their own miniature planetary systems. Using observations from the James Webb Space Telescope (JWST), researchers investigated eight young isolated objects with masses comparable to Jupiter’s.
These free-floating planets are difficult to observe due to their dimness and infrared radiation, making them crucial for understanding astrophysics questions. Unlike stars, they don’t accumulate enough mass to start fusion reactions in their cores. Theories suggest that some may form around a star before being ejected into space.
The researchers used JWST’s infrared instruments to study the objects in depth, finding six with excess emissions caused by warm dust and silicate grains indicating dust growth and crystallization – typical steps in rocky planet formation. This is the first detection of silicate emission in planetary-mass objects. The findings build on a previous paper showing that disks around free-floating planets can last millions of years, allowing for planet formation.
Lead author Dr. Belinda Damian says these discoveries show that planet-building blocks exist even around Jupiter-sized objects drifting alone. This suggests that planetary systems might form around lonely starless worlds, expanding our understanding of the universe’s potential.
Source: https://phys.org/news/2025-08-giant-free-planets-planetary.html