spacetoday.net: Water detected in exoplanet atmosphere

Posted: Thu, Apr 12, 2007, 8:26 AM ET (1226 GMT)
An astronomer has detected the first evidence of water in the atmosphere of an extrasolar planet. In a paper to be published in the Astrophyical Journal, Travis Barman reported the discovery of water in the planet HD209458b, a "hot Jupiter" that orbits close to its parent star, 150 light-years from Earth. The discovery was made possible through visible and infrared observations collected by the Hubble Space Telescope as the planet transited across the disk of the star: because of water absorption the planet blocks more starlight at infrared wavelengths than visible ones. Some scientists have expressed skepticism about the discovery, though, arguing that the data could also simply be instrument noise.