Astronomers using the European Southern Observatory’s Very Large Telescope (VLT) have discovered a record-breaking ‘growth spurt’ in a rogue planet, a free-floating world not bound to any star. The object, named Cha 1107-7626 and located 620 light-years away, is accreting material from its surrounding disc of gas and dust at the phenomenal rate of six billion tonnes per second. This is the strongest accretion rate ever recorded for any planetary-mass object.
This discovery provides revolutionary insights into planetary formation. The rogue planet, with a mass five to ten times that of Jupiter, is demonstrating that free-floating planets can be dynamic and active worlds. The observed accretion burst, which increased eight-fold in just a few months, suggests that at least some rogue planets form in a star-like manner. This blurs the traditional line between stars and planets.
Key to the findings, published in The Astrophysical Journal Letters, was the role of magnetic activity. The team, led by Víctor Almendros-Abad, found that a magnetic field likely channeled the dramatic infall of mass, a phenomenon previously only seen in young stars. Furthermore, the accretion episode altered the chemistry of the protoplanetary disc, with the appearance of water vapour during the burst.
This research, which also incorporated data from the James Webb Space Telescope, opens a new window into the nascent stages of these lonely worlds. The upcoming Extremely Large Telescope (ELT) will be instrumental in detecting more of these faint objects, helping to unravel the mystery of their origin—whether they form like stars or are ejected planets.
