A doomed "lava world" with a similar mass and density to that of Earth has been discovered orbiting a star 400 light-years away.
Observations suggest the planet, named Kepler 78b, is composed mostly of rock and iron, much like our own planet.
But its extremely close proximity to its host star - a hundredth of the distance between the Earth and the Sun - remains something of a puzzle.
Details of the work by two teams of researchers appear in Nature journal.
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