Rogue Planet Gains Mass at Astounding Rate, Challenging Planet Formation Theories
St Andrews, Scotland – Astronomers have observed a free-floating, “vagabond” planet rapidly gaining mass, a phenomenon previously only witnessed in stars. The planet, designated Cha 1107-7626, is accreting material at a rate of roughly a billion tons per second – comparable to the mass of comet 67P/Tschurjumow-Gerassimenko, the target of the European Rosetta mission.
The discovery, detailed in The Astrophysical Journal, utilized data from the Very Large Telescope (VLT) and the James Webb Space Telescope to analyze the planet’s growth during an “outburst” of accretion. Researchers found strong magnetic activity driving the acceleration of material onto the planet, a characteristic typically associated with stars.
Spectroscopic recordings taken during the accretion event revealed a change in the chemical composition of the surrounding disc,with the detection of water vapor – a phenomenon not previously observed in planetary systems.
“This discovery blurred the border between stars and planets and allows us to take a look at the earliest progress phases of loner planets,” said astronomer Belinda Damian from the University of St Andrews.
The origin of these vagabond planets remains a mystery. Theories include ejection from a star system or autonomous formation through the gradual accumulation of matter, similar to star formation. The observations of Cha 1107-7626 support the latter possibility for at least some of these objects.