First exoplanets directly imaged
Posted: Fri, Nov 14, 2008, 6:47 AM ET (1147 GMT)
Astronomers announced Thursday that they have for the first time directly imaged planets orbiting other stars. One team of astronomers reported directly observing three planets orbiting HR8799, a star 1.5 times the mass of the Sun 140 light-years from the Earth. Two of the planets were initially spotted in images from the Gemini North telescope in Hawaii, and were also seen, along with a third, in images from the neighboring Keck Observatory. The three planets are all relatively large, one with seven times the mass of Jupiter and the other two ten times as massive. Separately, the Hubble Space Telescope directly observed a planet orbiting the star Fomalhaut, 25 light-years away. The planet, located about ten times farther from the star than Saturn is from the Sun, weighs about three times the mass of Jupiter; its brightness suggests that it may have a large ring of ice and dust around it. The observations are the first time that extrasolar planets have been directly imaged from the Earth; previous discoveries have relied on indirect detection methods, such as Doppler shifts in stars caused by the gravitational tugs of orbiting planets.
Astronomers announced Thursday that they have for the first time directly imaged planets orbiting other stars. One team of astronomers reported directly observing three planets orbiting HR8799, a star 1.5 times the mass of the Sun 140 light-years from the Earth. Two of the planets were initially spotted in images from the Gemini North telescope in Hawaii, and were also seen, along with a third, in images from the neighboring Keck Observatory. The three planets are all relatively large, one with seven times the mass of Jupiter and the other two ten times as massive. Separately, the Hubble Space Telescope directly observed a planet orbiting the star Fomalhaut, 25 light-years away. The planet, located about ten times farther from the star than Saturn is from the Sun, weighs about three times the mass of Jupiter; its brightness suggests that it may have a large ring of ice and dust around it. The observations are the first time that extrasolar planets have been directly imaged from the Earth; previous discoveries have relied on indirect detection methods, such as Doppler shifts in stars caused by the gravitational tugs of orbiting planets.
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