ESA's Hipparcos Satellite Observed an Extrasolar Planet 8 Years Ago.

According to ESA: "Astronomers have just realised that news of a planet orbiting a distant star came from ESA's Hipparcos satellite eight years ago, although no one noticed it until now.

Nöel Robichon and Frédéric Arenou of the Observatoire Paris-Meudon have re-examined sightings of the star HD 209548, by the Hipparcos star-mapping mission during its life in orbit, 1989 to 1993. They find, among 89 observations, that the star's light was slightly dimmed on five occasions by the shadowof a large planet passing in front of it. The French astronomers looked closely at the Hipparcos data when they heard that colleagues in the USA, monitoring this star from the ground, saw it diminish in intensity for two and a half hours, on two occasions in September 1999."

° Press release, ESA
° Hipparcos website
° Hipparcos Epoch Photometry Search facility
° Extrasolar Planets, SpaceRef Directory
° Extrasolar Planets, The Astrobiology Web

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