Identification of Exoplanet Host Star

Identification of Exoplanet Host Star

About this image

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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.

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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 color 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.


Tags
Exotic, Extrasolar Planets, Gravitational Lensing, Hubble Telescope, Illustrations, Planets, Stars

Credits

Credit: NASA, ESA, A. Feild (STScI), D. Bennett (University of Notre Dame), and J. Anderson (Rice University)