10 new planets found in last six months
1 Apr 2008
In the last six months an international team of astronomers have used two batteries of cameras, one in the Canary Islands (above) 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 (SuperWASP) was announced by team member Dr Don Pollacco of Queen's University Belfast, at the Royal Astronomical Society's National Astronomy Meeting today.
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 the planet moves it 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.
SuperWASP 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 SuperWASP 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. The transit method also allows scientists to reduce the size and mass of each planet.
Each possible planet found using SuperWASP is then observed by astronomers working at the Nordic Optical Telescope on La Palma, the Swiss Euler Telescope in Chile (left) and the Observatoire de Haute Provence in southern France, who use precision instruments to confirm or reject the discovery.
Forty-five planets have now been discovered using the transit method, and since they started operation in 2004 the SuperWASP cameras have found 15 of them—making them by far the most successful discovery instruments in the world. The SuperWASP 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 is just 1.1 Earth days. The planet is so close to its star that its daytime temperature could reach a searing 2,300 degrees Celsius.
Dr Pollacco is delighted with the results. 'SuperWASP is now a planet-finding production line and will revolutionise the detection of large planets and our understanding of how they were formed. It's a great triumph for European astronomers.'
Adapted from information issued by Queen's University Belfast.
