In the vast, dark expanse of space, a lone wanderer is experiencing a dramatic growth spurt.
This isn’t a star, but a mysterious rogue planet, a world untethered to any Sun, and it is currently devouring material from its surroundings at a mind-boggling rate.
Groundbreaking new research from the University of St Andrews has caught this celestial nomad in the act, revealing the strongest planetary growth rate ever recorded and offering unprecedented clues about how these lonely worlds evolve.
Catching a cosmic eater in the act
Located approximately 620 light-years away in the constellation of Chamaeleon, the rogue planet, known as Cha 1107-7626, is a colossal object, with a mass estimated to be five to ten times that of Jupiter.
Unlike the planets in our solar system, it drifts freely through the cold darkness of interstellar space. Yet, it is not entirely alone; it is still forming, surrounded by a disc of gas and dust.
An international team of astronomers, using the powerful X-shooter spectrograph on the European Southern Observatory’s Very Large Telescope (VLT) in Chile, has discovered that this planet’s growth is anything but steady.
Their observations revealed a sudden, violent burst of accretion. The rate at which material was falling onto the planet skyrocketed, reaching an astonishing six billion tonnes every second – a rate eight times faster than what was observed just a few months prior.
Blurring the line between stars and planets
This discovery does more than document a planetary feeding frenzy; it challenges our fundamental understanding of how celestial bodies form.
The origin of free-floating planets has long been a puzzle. Are they failed stars, or were they giant planets ejected from their home solar systems?
The recent observations strongly suggest that at least some rogue planets form in a manner strikingly similar to stars.
The dramatic burst of accretion, a phenomenon previously spotted in young stars, indicates a shared formation path.
This finding effectively blurs the traditional boundary that separates planets from their stellar counterparts.
Adding to the stellar parallels, the research team found that magnetic activity appears to be driving this incredible infall of mass.
This marks the first time such a magnetic mechanism has been observed in a planetary-mass object, suggesting that even these low-mass wanderers can generate powerful magnetic fields.
A changing chemical signature
As the team delved deeper, they uncovered another first. By comparing the light emitted from the system before and during the accretion burst, they detected a significant chemical change in the planet’s surrounding disc.
Water vapour was present during the intense feeding episode but was absent beforehand.
This transient chemical signature, another behaviour once thought to be exclusive to stars, provides a dynamic new insight into the physical conditions around a growing rogue planet.
It paints a picture of a chaotic, evolving environment where rapid changes leave distinct chemical markers.
The future of hunting lonely worlds
Free-floating planets are notoriously difficult to study due to their faintness. However, the future of this field is bright.
The upcoming Extremely Large Telescope (ELT), set to operate under the pristine skies of the Atacama Desert, promises to revolutionise this area of astronomy.
With its colossal mirror and suite of powerful instruments, the ELT will be able to hunt for and characterise many more of these enigmatic, lonely worlds.
Each new discovery will help astronomers piece together the life story of rogue planets, finally answering the question of just how star-like these dark, wandering giants truly are.
