Researchers confirm the existence of water on an extrasolar planet

15 July 2007


For the first time researchers have been able to say with certainty that there is water on a distant planet.

Writing in this week's Nature, UCL's Giovanna Tinetti and her colleagues used NASA's Spitzer Space Telescope to study a "hot-Jupiter" orbiting a star 60 light years away. Like our own Jupiter the planet's a gas giant, but unlike our solar system it sits very close to the parent star, completing an orbit in just 2.2 days. The team were able to watch as the planet eclipsed the star on each orbit and look for the infrared fingerprint of water in the starlight passing through the planet's outer atmosphere. "We can now say with some security that the water signal is definitely there", says Giovanna Tinetti.

But it's unlikely that the planet will become a holiday destination any time soon. It's so close to the parent star that the sunlit side is a sizzling 1200 degrees celsius and even the dark side is a roasting 800 degrees C. As a result it's too inhospitable for life, but, as Tinetti points out, "our discovery shows that water might be more common out there than previously thought. Our method can be used in the future to study more 'life-friendly' environments."

Planet HD189733b also made headlines earlier this year when scientists were able to forecast its weather.


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