London, Feb 3 (ANI): The Hubble Space Telescope has spotted an exoplanet in an image that was captured 10 years ago, which raises hope that more planets lie buried in Hubble's vast archive.
In 1998, Hubble studied the star HR 8799 in the infrared, as part of a search for planets around young and relatively nearby stars. The search came up empty.
Last year, Christian Marois of the Herzberg Institute of Astrophysics in Victoria, British Columbia, Canada, and colleagues looked at the same star using the Gemini North telescope in Hawaii.
They discovered three planets, each about 10 times as massive as Jupiter. They succeeded where the Hubble team failed mainly because of new strategies developed to carefully subtract the star's glare, leaving only the faint infrared glow from its planets.
Now, according to a report in New Scientist, Marois and David Lafreniere, of the University of Toronto in Ontario, Canada, decided to apply their new mathematical tools to the decade-old Hubble image.
This involved digitally combining Hubble's views of 23 similar stars that do not have planets to create a reference image nearly identical to that of HR 8799.
When they subtracted the reference image from HR 8799's, the outermost of its three planets popped into view.
"I felt the same excitement I experienced when we discovered it the first time," said Lafreniere.
This opens the door for the discovery of exoplanets simply by reprocessing old Hubble images, according to Bruce Macintosh of Lawrence Livermore National Laboratory in California.
He suggests that images of at least 200 stars that had been the target of Hubble's exoplanet searches should be re-analyzed using the new method, to uncover hitherto undetected planets. (ANI)