HD 189733b passing in front of its star with zoom (artist's impression)

The new observations were made as the extrasolar planet, dubbed HD 189733b, passed in front of its parent star in a transit. Here the transit is seen in an artist's impression from a vantage point a few hundred thousand kilometres from the planet. As the light from the star passes through the atmosphere around the limb of the giant extrasolar planet, the gases in the atmosphere stamp their unique signature on the starlight from HD 189733.

Credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)