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Huge Exoplanet Discovery Prompts Scientists to Re-Think Planetary Theory |
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Written by Staff Writer
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Aug 07, 2007 at 06:17 PM |
The ongoing search for planets orbiting other stars has recently stumbled across "TrES-4", "the largest known exoplanet" according to Georgi Mandushev, who heads the planet hunting team at the Lowell Observatory in Flagstaff, USA.
TrES-4 has been found as part of the Transatlantic Exoplanet Survey (TrES), an ongoing project which hopes eventually to be able to refine its technical capabilities in order to detect small, Earth like planets, which are much harder to spot. This is because the primary method of planet finding - the deduction of a planet's presence and characteristics from its distortion of the light from its star - would require as-yet unobtainable access to telescopes powerful enough to observe the much smaller effect on a star's light which an earth-like planet, by necessity, would exert.
The TrES team came across the planet in orbit around the star GSC02620-00648, located some 1500 light years distant from our sun, while scanning the Hercules constellation.
The newly discovered body is about 75% larger than our local gas giant heavyweight, Jupiter, but intriguingly it has a lower mass, suggesting that it has a very low density - just 0.2 grams per cubic centimetre, which in theory should mean that the planet would be buoyant in water. Its incredibly close proximity to GSC02620-00648 has lead the planet hunters at TrES to conclude that the planet is very hot, perhaps reaching temperatures of up to 1400 degrees centigrade. Because of this proximity, scientists are speculating that the upper layers of the planet's atmosphere may even be periodically boiled away, creating a trail of vapour - very much akin to the tail of a comet - behind the planet as it completes its phenomenally short orbit of three and a half days.
The size of TrES-4 has sent many planetary theorists back to the drawing board, as there is no current satisfactory explanation in the field as to how such a huge planet could form, and remain intact, in such close proximity to its star. The phenomenon seems to fly in the face of accretion theory, which dictates that large gaseous planets will tend to form at larger distances from the solar centre. Francis O'Donovan, a graduate student from Caltech, was eager to draw attention to the significance of this, the most recent and impressive case in a string of discoveries concerning gas giants in close proximity to a star. The findings, he said, could play a big part in improving our understanding of the formation of our own solar system.
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Last Updated ( Aug 29, 2007 at 10:39 AM )
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