Astronomers record "growth spurt" in rogue planet

Astronomers have observed an unprecedented “growth spurt” in a free-floating planet outside of the solar system, which is consuming gas and dust from its surroundings at a rate of six billion tonnes per second. Researchers say it is the strongest planetary growth rate ever recorded.

The findings, published in The Astrophysical Journal Letters, were made using the European Southern Observatory (ESO) in Chile’s Atacama Desert, The Independent writes.

Víctor Almendros-Abad, lead author of the study, said: “People may think of planets as quiet and stable worlds, but with this discovery we see that planetary-mass objects freely floating in space can be exciting places.”

The planet, officially named Cha 1107-7626, is located about 630 light-years away in the constellation Chamaeleon and has a mass five to ten times greater than Jupiter’s. Scientists found that its rate of accretion — the process of absorbing material from its environment — has been highly unstable. By August 2025, it was growing approximately eight times faster than in previous months.

“This is the strongest accretion episode ever recorded for a planetary-mass object,” Almendros-Abad added.

The team also drew on data from the James Webb Space Telescope and the SINFONI spectrograph, operated by the US, European and Canadian space agencies.

Aleks Scholz, co-author and astronomer at the University of St Andrews, said: “The origin of rogue planets remains an open question: are they the lowest-mass objects formed like stars, or giant planets ejected from their birth systems?”

By comparing light emitted before and during the burst of growth, researchers found that magnetic activity likely played a role in the accretion — a mechanism previously observed only in stars. This suggests even low-mass objects can generate magnetic fields strong enough to power the process, hinting that some rogue planets may share a similar formation pathway with stars.

Another stellar-like feature was a chemical transformation in the planet’s surrounding disc, with water vapour detected during the accretion episode but not before.

Belinda Damian, another co-author from the University of St Andrews, noted: “This discovery blurs the line between stars and planets and gives us a sneak peek into the earliest formation periods of rogue planets.”

ESO astronomer Amelia Bayo added: “The idea that a planetary object can behave like a star is awe-inspiring and invites us to wonder what worlds beyond our own could be like during their nascent stages.”

By Sabina Mammadli