Imagine a planet so hungry, it swallows billions of tonnes of matter every second -- and it doesn't even orbit a star! Scientists have recently observed a rapidly growing 'baby planet' in space named Cha 1107-7626. Unlike a star, this object is a free-floating planetary body.
What has truly amazed astronomers is the planet's extraordinary growth rate: it consumes around 6 billion tonnes of material every second! Although it's 5 to 10 times larger than Jupiter, it falls well below the threshold for star formation (80 Jupiter masses) or even brown dwarf classification (13 Jupiter masses). Yet, its behaviour is anything but typical.
Astronomers estimate that Cha 1107-7626 absorbs roughly 10 Jupiter masses of material per year, and this intense feeding continued for at least two months. The findings were recently published in The Astrophysical Journal Letters.
Typically, intense accretion events like these are seen in stars or brown dwarfs, not in planetary-mass objects. However, Cha 1107-7626 suddenly became 3 to 6 times brighter and displayed hydrogen emission lines, a clear sign of magnetic accretion, usually associated with stars.
Researchers now believe that Cha 1107-7626 likely formed on its own, rather than around a star before being ejected. This suggests it formed directly from the gravitational collapse of a cloud of gas and dust, much like a star would.
Although first discovered in 2008, it wasn't until 2025 that scientists, using the European Southern Observatory's Very Large Telescope (VLT) and NASA's James Webb Space Telescope (JWST), uncovered more of its secrets.
Observations with the X-shooter instrument showed it was accreting material from a surrounding disc, containing silicates, hydrocarbons, and even water vapour, essentially forming a miniature solar system around the planet.
Records from 2016 show that Cha 1107-7626 exhibited similar behaviour, indicating this isn't a one-off event. Instead, the baby planet seems to go through periodic feeding bursts, showing intense accretion phases from time to time.
This discovery has challenged previous assumptions. Planetary-mass objects are generally thought to be quiet and stable, but Cha 1107-7626 defies this norm. As one astronomer put it, "It's remarkable to think that even planets can behave like stars."
The case of Cha 1107-7626 suggests that planet and star formation may be more diverse and complex than previously thought.