Water has been found for the first time in the atmosphere of a planet outside the solar system.
The discovery increases the chances of life being found among the stars.
The planet, nicknamed Osiris by astronomers, orbits so close to its parent star that its surface reaches a scorching 1,100C.
It has already given scientists a number of surprises. Osiris, which is 150 light years from Earth and has the official title HD 209458b, was the first extra-solar world known to have an atmosphere, mainly composed of hydrogen. But its atmosphere was found to be boiling away into space.
In 2004, astronomers revealed that the planet's outer atmosphere contained carbon and oxygen, thought to be swept up from the deeper levels by the flow of escaping hydrogen. The new discovery of water vapour emerged from measurements taken as Osiris passed directly in front of its parent star.
Dr Travis Barman, who led the US team from the Lovell Observatory in Arizona, said: "We now know that water vapour exists in the atmosphere of one extra-solar planet and there is good reason to believe that other extra-solar planets contain water vapour."Reuse content