LONDON-Astronomers have discovered a giant planet that, they say, should not exist, according to current theories.

The Jupiter-like world is unusually large compared with its host star, contradicting a widely held idea about the way planets form.

The star, which lies 284 trillion km away, is an M-type red dwarf - the most common type in our galaxy.

An international team of astronomers has reported its findings in the journal Science.

“It’s exciting because we’ve wondered for long a time whether giant planets like Jupiter and Saturn can form around such small stars,” said Prof Peter Wheatley, from the University of Warwick, UK, who was not involved with the latest study.