Identification of Extrasolar planet Host Star

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Hubble Space telescope observed and identified the host star to a gravitationally lensed planet first discovered in 2003 by ground-based telescopes.

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A foreground red star and planet drifts toward the sky position of a much farther sunlike background star.

In 2003, the foreground star-planet system slightly amplifies the light of a background star that momentarily aligns with it. This is called a microlensing event.

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The light from each star is progressively more offset year after year as the foreground star drifts by.

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In 2005, Hubble Space Telescope observations distinguished the light from the two stars. This was possible because the foreground star turns out to be a different colour from the background star. By observing the stars though a red and blue filter, astronomers were able to enhance the visibility of the offset. The relative offset is 0.7 milliarcseconds (the angular width of a dime seen 3,000 miles away) from the source star. (This is below Hubble's resolution, but still a measurable effect.) The deduced positions of the two stars in 2005 are shown with red and blue crosshatches.


NASA, ESA, D. Bennett (University of Notre Dame), and J. Anderson (Rice University)

About the Image

NASA press release
NASA caption
Release date:8 August 2006, 19:00
Size:2100 x 2162 px

About the Object

Name:MOA 2003-BLG-53, OGLE-2003-BLG-235L
Type:• Milky Way : Star
• Milky Way : Star : Circumstellar Material : Planetary System

Image Formats

Large JPEG
733.8 KB
Screensize JPEG
264.3 KB


Colours & filters

Hubble Space Telescope
Hubble Space Telescope

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