Explanation
Previously unknown extrasolar planets-planets outside our solar system- probably await discovery In archival images taken by the Hubble Space Telescope. A new technique allows astronomers to model the amount and distribution of scattered light produced by young stars suspected of spawning planets and remove that light from images of those stars. Once the glare of the parent stars' light is removed, planets may show up In Images already taken by Hubble's infrared cameras, since heat emitted by planets produces telltale wavelengths of infrared light.
In 2008, astronomers using powerful Earth-based telescopes were able to detect three planets orbiting the star HR 8799 that were not previously detected by astronomers who examined infrared Hubble images of the star in 1998. David Lafrentere-a member of the team of astronomers who detected the planets in 2006 -then applied the new technique to those Hubble images and managed to uncover the outermost of the three planets.
The others, tying closer to the star, still could not be distinguished against the background of the star's light.
Lafrenifre's work has helped reaffirm the importance of maintaining long-term archives, and-because Hubble's infrared cameras record some wavelengths of light that cannot penetrate through the atmosphere to reach Earth's surface-revealed new information about the outermost of HR 8799's planets.