HD 209458
From Free net encyclopedia
HD 209458 is an 8th magnitude star in the constellation Pegasus. It is very similar to our Sun, and it is classified as a yellow dwarf (spectral class G0 V). Because it is located at a distance of about 150 light years, it is not visible to the unaided eye. With good binoculars or small telescope it should be easily detectable.
Image:Pegasus HD209458 location.png
In 1999 two teams working independently (one team consisted of astronomers at the Geneva Observatory, the Harvard-Smithsonian Center for Astrophysics, and the Wise Observatory; the second group was the California and Carnegie Planet Search team) discovered an extrasolar planet orbiting the star by using the radial velocity planet search method. Soon after the discovery, separate teams led by David Charbonneau and Gregory W. Henry were able to detect a transit of the planet across the surface of the star making it the first known transiting extrasolar planet. The planet received the designation HD 209458 b.
Because the planet transits the star, the star is dimmed by about 2% every 3.5 days making it an extrinsic variable. The variable star designation for HD 209458 is V376 Pegasi.
HD 209458 b
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HD 209458 b is an exoplanet discovered in 1999.