'Theoretical models suggest that the planet may have lava or boiling oceans on its surface. With such extreme conditions, this planet is definitively not a place for life to develop.'

The planet is about 500 light years from Earth and orbits a young, cool star in the Monoceros constellation.

The exoplanet's discovery was announced in February, but scientists required further examination before announcing with confidence details of its environment. They used a telescope in Chile to take very detailed measurements, determining it had a radius less than twice that of Earth and a mass five times as large.

It is the smallest exoplanet detected so far.

The findings are to be published in October in the US-based journal Astronomy and Astrophysics.