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A rogue planet with a mass more than 12 times that of Jupiter has been spotted hurtling through space.

This brownish celestial body is travelling through the galaxy completely alone around 20 light years from Earth and has an unusual aurora emanating from its pole.

The planet produces a magnetic field around 200 times greater than that of the largest planet in our Solar System.

It is the first object of its kind to be spotted using radio signals, the Daily Mail reports. 

Scientists are unsure of its origin and what causes its mysterious aurora.

The unusual object sits in a grey area between a star and a planet, and was originally classed as a 'brown dwarf' - a failed star.

Brown dwarfs are objects that are too big to be considered planets, but not massive enough to sustain nuclear fusion in their cores — the process that powers stars.

It was first seen in 2016 by the Very Large Array (VLA) telescope in New Mexico that specialises in detecting radio signals.

The telescope spotted five objects, which scientists believed were all brown dwarves.

Further research however, saw that one of the objects, called SIMP J01365663+0933473, was considerably younger and smaller than the others.

A team of astronomers found it has a surface temperature of about 825°C (1,517°F) and is only 200 million years old.

Some experts have concluded it is therefore not a brown dwarf, but a free-floating planet.

"This object is right at the boundary between a planet and a brown dwarf, or 'failed star', and is giving us some surprises that can potentially help us understand magnetic processes on both stars and planets," said Dr Melodie Kao, an astronomer at Arizona State University.   

The mystique around the celestial wanderer challenges the traditional understanding of how objects in space interact. 

The exact difference between a large gas planet and a brown dwarf is a bone of contention for scientists, with debate raging over what defines one or the other.

One measure used by astronomers is the mass of an object when deuterium - an isotope of hydrogen - stops fusing in the object's core.