The WASP factory finds 10 new planets in the last 6 months (4/2/2008)

Discoveries of extrasolar planets made by international team of astronomers.

In the last 6 months an international team including astronomers from the University of Leicester have used two batteries of cameras, one in the Canary Islands and one in South Africa, to discover 10 new planets in orbit around other stars (commonly known as extrasolar planets). The results from the Wide Area Search for Planets (WASP) will be announced by the team at the RAS National Astronomy Meeting (NAM 2008) on Tuesday 1 April.

Scientists have found more than 270 extrasolar planets since the first one was discovered in the early 1990s. Most of these are detected through their gravitational influence on the star they orbit - as it moves the planet pulls on the star, tugging it back and forth. However, making these discoveries depends on looking at each star over a period of weeks or months and so the pace of discovery is fairly slow.

WASP uses a different method. The two sets of cameras watch for events known as transits, where a planet passes directly in front of a star and blocks out some of the star's light, so from the Earth the star temporarily appears a little fainter. The WASP cameras work as robots, surveying a large area of the sky at once and each night astronomers have data from millions of stars that they can check for transits and hence planets.

Each possible planet found using WASP is then observed by astronomers working at the Nordic Optical Telescope on La Palma, the Swiss Euler Telescope in Chile and the Observatoire de Haute Provence in southern France, who use precision instruments to confirm or reject the discovery.

45 planets have now been discovered using the transit method, and since they started operation in 2004 the WASP cameras have found 15 of them - making them by far the most successful discovery instruments in the world. Transiting planets are particularly prized by astronomers as it is possible to calculate their size and mass and even to study the composition of their atmospheres. The WASP planets have masses between a middleweight 0.5 and a huge 8.3 times that of Jupiter, the largest planet in our Solar System. A number of these new worlds are quite exotic. For example, a year on WASP-12B (its orbital period) is just 1.1 days. The planet is so close to its star that its daytime temperature could reach a searing 2300 degrees Celsius.

Dr Richard West, who leads the WASP team at Leicester, is delighted with the results. "WASP is now delivering new planet discoveries in world-beating numbers. We expect to find many more in the years to come, and they will help us to explain how planetary systems, such as our own Solar System, are formed and how they evolve" said Dr West.

Note: This story has been adapted from a news release issued by the University of Leicester

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