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PARIS (AFP) - Astronomers announced this week that they had detected 10 new planets outside our Solar System, including a tantalizing Jupiter-sized giant found almost in the Earth's "backyard." The discoveries add enormously to the tally of around 40 extra-solar planets, existence of which was first uncovered only five years ago and which has sparked fevered speculation about the prospects for life elsewhere in the Universe. The most exciting finding is a gas giant about the size of Jupiter which orbits Epsilon Eridani, the fifth brightest star in the constellation Eridanus and one that is closely similar to the Sun. Epsilon Eridani is 10.49 light years from Earth, a tiny distance in galactic terms, which opens up the possibility that its planet could be directly photographed by one of the Earth's big orbiting telescopes, such as the Hubble. William Cochran, an astronomer at the University of Texas' McDonald Observatory, which worked with renowned planet-hunters in California and Europe, said the discovery "is like finding a planet in our own backyard, relatively speaking." "Not only is this planet nearby, it lies 478 million kilometers (297 million miles) from its central star - roughly the distance from the Sun to the asteroid belt in our own solar system," Cochran said. The astronomers were to present their findings Monday at the general assembly of the International Astronomical Union (IAU), an umbrella of national associations that acts as a sorting house for research, confirms discoveries and assigns names to heavenly bodies. The assembly, meeting in Manchester, northern England, from Monday until August 18, gathers only every three years. The apparent similarity between Jupiter and the planet spotted at Epsilon Eridani is of major interest, Cochran said in a press statement issued by the IAU. Jupiter is thought by some astronomers to have played a vital role in nurturing life on Earth. This is because its huge gravitational pull acts as a protective barrier that attracts dangerous asteroids and comets, preventing them from smashing into our planet. "Having a large planet orbiting fairly far out from Epsilon Eridani means there could be room for Earth-like planets in a reasonably stable orbit closer into the star," Cochran said. "All the planets found so far that are the size of Jupiter are much closer to the parent star. It means there could be room for an Earth-like planet closer to Epsilon Eridani and - perhaps - in a habitable zone," he said. If the new planet can be photographed directly, that too would be a breakthrough for space imaging. Extra-solar planets are usually detected by computer, thanks to the "wobble" their gravitational pull exerts on a star. The magnitude and nature of the "wobble" can be used to calculate the position, orbit and size of the planet. Last year, astronomers got a break when they photographed a dimming in the light coming from star HD 209458, about 150 light-years from Earth. That phenomenon was caused by a planet passing in front of the Earth, and gave the first visual, albeit indirect, proof of a planet outside our Solar System. Of the nine other new planets, six were spotted by a Geneva-led team, CORALIE, while the others were found by American astronomers Debra Fischer, Geoffrey Marcy and Paul Butler, the IAU said. All are leaders in this specialized but fast-growing field. "We're now at a stage where we are finding planets faster than we can investigate them and write up the results. It's wonderful," Marcy said. All of these so-called exoplanets are anonymous at present. One of the tasks of the Manchester meeting will be to draw up a global policy on how and what to name these new phenomena
Newswires |
