Astrometry nabs an exoplanet | Science News

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Astrometry nabs an exoplanet

Long-proposed search method finally finds what it’s been looking for

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12:23pm, June 1, 2009

Researchers for half a century have tried — and failed — to use the motion of stars moving across the sky to discover planets that lie beyond the solar system. Now a team has finally used the method, known as astrometry, to find one of these orbs. The newfound extrasolar planet, six times heavier than Jupiter, orbits the low-mass star VB 10 some 20 light-years from Earth, report Steven Pravdo and Stuart Shaklan of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., in an upcoming Astrophysical Journal.

The traditional method of identifying extrasolar planets, which now number more than 350, relies on tracking the velocity of a parent star along the line of sight to Earth — rather than across the sky. Because an orbiting planet pulls its parent star ever so slightly to and fro, the star’s line-of-sight motion speeds up and slows down periodically, revealed by telltale shifts in the color of starlight recorded from Earth. This techniqu

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