Exoplanets revealed in old Hubble data.
With a powerful, newly refined image-processing technique numerous extrasolar planets are laying, waiting to be discovered in decade's worth of Hubble Space Telescope archival data. As a demonstration of this technique an exoplanet that was previously hidden in the glare of the light of the host star spilling past the coronagraph, was recently revealed in an 1998 Near Infrared Camera and Multi-Object Spectrometer (NICMOS) image. The planet, estimated to be at least seven Jupiter masses, was originally discovered in images taken with the Keck and Gemini North telescopes in 2007 and 2008 respectively. It is the outermost of three massive planets known to orbit the dusty young star HR 8799, which is 130 light years away. NICMOS could not see the other two planets because its coronagraphic spot (a device which blots out the glare of the star) also interferes with observing the two inner planets.
The new image-processing technique is an adaptation of image reconstruction methods first developed for ground-based observatories. It efficiently subtracts the glare from a star that spills over the coronagraph's edge, allowing planets that are one-tenth the brightness of what could be detected before with Hubble, to become visible.
This is a NICMOS coronagraphic image of a planet orbiting the star HR 8799, located 130 light-years away. The coronagraph has been used to block the light from the bright star (black circle) allowing the search for the dim glow Of the planet HR 8799b. Credit: NASA, ESA, and D. Lafreniere (University of Toronto, Canada)
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|Title Annotation:||news notes; Hubble Space Telescope|
|Publication:||Monthly Notes of the Astronomical Society of Southern Africa|
|Article Type:||Brief article|
|Date:||Jun 1, 2009|
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