Rogue planets live by their own rules, freely floating through the cosmos without being bound to a star. With no stellar supervision, those isolated planetary bodies can often behave in unusual ways. Astronomers discovered a rogue planet experiencing a rather unusual growth spurt, bingeing on its surrounding gas and dust at an unprecedented rate.
The rogue planet is located approximately 620 light-years away in the Chameleon constellation. It’s still in its early formation process and is feeding off a surrounding disc of gas and dust, the leftovers from its birthing process. Using the European Southern Observatory’s (ESO) Very Large Telescope, the team of scientists behind the recent discovery revealed that the planet, officially named Cha 1107-7626, is eating the material at a record-breaking rate of 6 billion tons per second.
The discovery is detailed in a paper[1] published Thursday in The Astrophysical Journal Letters, detailing the strongest growth rate ever observed in any planetary body.
Feeding time
Rogue planets can form in two ways. They are either born around a star and later evicted from their cosmic home by interacting with other bodies in the system, or they form independently in the aftermath of the collapse of a cloud of gas and dust. The free-floaters still have discs of material around them, the remnants of their formation process. While still in their growing phase, planets typically feed on the gas and dust found in the protoplanetary disc surrounding them in a process called accretion.
For Cha 1107-7626, the rate at which it is accreting material is not steady. By observing the planet over time, the astronomers behind the new study found that by August, it had started accreting material around eight times faster than it was just a few months earlier.
“This is the strongest accretion episode ever recorded for a planetary-mass object,” Víctor Almendros-Abad, an astronomer at the Astronomical Observatory of Palermo, National Institute for Astrophysics (INAF), and lead author of the new study, said in a statement[2]. “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.”
Although still young, the planet is already a big boy with a mass five to 10 times that of Jupiter’s. The team of astronomers also discovered that its unusual growth may be attributed to its magnetic activity, causing material to fall into the disc at a remarkably high rate.
The chemistry of the disc surrounding the planet seems to have also changed during its accretion, with the team detecting water vapor during the process but not before. This type of activity has only ever been observed on stars, suggesting that even planetary objects with lower mass can have strong enough magnetic fields to drive their accretion.
“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,” Amelia Bayo, ESO astronomer and co-author of the study, said in a statement.