Rogue planets host their own mini planetary systems

Starless, free-floating giant worlds may build rocky planets of their own

- Jamie Middleton

When we imagine planets, we usually picture them circling a fiery star like our Sun. But new evidence has now been found of a type of planetary system that instead forms around cold planets that float free through the cosmos.

Using JWST's powerful infrared instruments, astronomers at the University of St Andrews in the UK have discovered dusty discs around a selection of these 'rogue' worlds. Spectroscopic analysis revealed that the planets, each 5–10 times the mass of Jupiter, have discs with the same composition as the protoplanetary discs found around young stars, from which planets typically coalesce.