Strange twin planets found

A few dozen such objects have been identified in recent years but this is the first set of "twins".

Dubbed "planemos", they circle each other rather than orbiting a star.

Their existence challenges current theories about the formation of planets and stars, astronomers report in the journal Science.

"This is a truly remarkable pair of twins - each having only about 1% the mass of our Sun," said Ray Jayawardhana of the University of Toronto, co-author of the Science paper.