Extrasolar Planets: May 2008

Presenter: Giovanna Tinetti, University College, London

Date/Time: June 2, 2008 11:00 AM Pacific

Abstract: In the past decade, over 280 planets orbiting other stars (extrasolar planets) have been discovered. For a growing sample of giant extrasolar planets orbiting very close to their parent star (hot-Jupiters), we can already probe their atmospheric constituents using transit techniques. With this method, we can indirectly observe the thin atmospheric ring surrounding the optically thick disc of the planet -the limb- while the planet is transiting in front of its parent star. This method was traditionally used to probe the atmospheres of planets in our Solar System and most recently, thanks to the Hubble and Spitzer Space Telescopes, was successfully applied to exoplanets.

Former NAI Postdoctoral Fellow Giovanna Tinetti is co-author on a groundbreaking paper in Nature detailing the observation of methane and water vapor in the atmosphere of the extrasolar planet HD 189733b. The team used the NASA Hubble Space Telescope to observe the transiting exoplanet, using the NICMOS camera to obtain a spectrophotometric time series. This result is a milestone in the search for life elsewhere in the Universe, most importantly because it demonstrates that we have the technology to identify these molecules in exoplanet atmospheres.

[Source: NAI newsletter]