UK boffins ID three new exo-planets

Robotic sky scanner comes up trumps

Planet-hunting boffins based in the UK have announced the discovery of three more spinning globes to add to the more than 200 extrasolar planets already known to science. The planets turned up during the Wide Area Search for Planets (WASP).

All are gas giants, roughly the size of Jupiter, and are orbiting their parent stars so tightly that they whip around them in a matter of days.

According to Professor Andrew Cameron, of St Andrews University, they have some of the shortest "years" of any exo-planets yet discovered. Their proximity to their parent stars means the surface temperatures are likely to be approaching 2,000°C, so even if they were small and rocky, they'd be pretty unpleasant places for fragile humans to visit.

The planets were all identified because they transit their parent stars. As they pass in front of the star, they block some of the light that is heading for Earth. These tiny dips in brightness alert eagle-eyed astronomers to their existence, and add to our overall understanding of how planets form.

"When we see a transit we can deduce the size and mass of the planet and also what it is made of, so we can use these planets to study how solar systems form," said Dr Coel Hellier of Keele University.

One of the planets was found in the skies above the northern hemisphere, while the other two are in the south. The discovery of the two southern planets makes the WASP team the first to have spied other worlds in each hemisphere.

The two southern planets, WASP-4 and 5, were discovered by researchers using the project's camera in South Africa. Swiss researchers then confirmed the find, and that the planets are the brightest transiting planets in the southern skies. WASP-3 is the third discovery to come from the project's SuperWASP camera in the Canary Islands.

SuperWASP is a UK-led planet hunting project comprising eight academic institutions, including Cambridge University, the Instituto de Astrofisica de Canarias, and Keele University.

The project uses two robotic observatories - in the Isaac Newton Group of telescopes (ING) on La Palma and South African Astronomical Observatory (SAAO), just outside Sutherland, South Africa. These scan the skies for the characteristic dips in brightness than indicate a transiting planet. The robots operate without a break, all year round, providing researchers with a map of the whole sky.

The discovery of the three worlds is being announced by the WASP project this week at an international conference on extrasolar planets in Suzhou, China. ®

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