No such planet exists
when Michel Mayor and Didier Queloz announced the detection of an extr-asolar planet about a year ago, there was a lot of excitement in the field of planetary sciences. Soon, the discovery was confirmed by others, and more than that some seven other planets were supposed to have been discovered. But now come reports from David Gray of the University of Western Ontario denying this discovery. The Canadian astronomer claims that the signal which was seen by Mayor and Queloz was misinterpreted by them. What Mayor and Queloz saw was a wobble in the orbit of the star 51 Pegasi, just outside the Great Square of Pegasus (Nature, Vol 385, No 6619).
This four day cycle in the velocity of the star was interpreted as the effect of a huge planet (almost half the size of Jupiter) in a tight orbit around the star. The orbital radius of the planet is inferred to be about 15 per cent that of the orbital radius of mercury around the Sun.The wobble is detected by the shifting in wavelength of the light emitted from the star's surface. The light from the parts moving towards us is blue shifted, while light from the portions moving away is red shifted. Mayor and Queloz analysed about 5,000 spectral lines in the visible spectrum and detected the wobble and the presence of the planet. David Gray has carried out observations of the 51 Pegasi at a much higher spectral resolution than before.
He claims that the planetary hypothesis is unnecessary, since the four day cycle can be explained on the basis of a complex sloshing process on the star's surface. These oscillations on the star's surface, though hitherto never seen in a star of the size of 51 Pegasi, could mimic the motion caused by a planetary companion. In a major exchange being carried out over the World Wide Web, the original discoverers of the 'planet' have rebutted Gray's conclusions as being too premature. They claim that the observations made by Gray may have an alternate explanation. While most astronomers are not willing to accept Gray's hypothesis of the star oscillating (it is hard to imagine a massive Sun like star having upheavals on its surface with such persistence), they do believe that many more observations at better spectral resolution are needed to settle the issue.
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