This artist’s impression shows several comets speeding across a vast protoplanetary disc of gas and dust and heading straight for the youthful, central star of the system. These 'kamikaze' comets will eventually plunge into the star and vaporise. The comets are too small to be imaged, but their gaseous spectral 'fingerprints' on the star's light were detected with the NASA/ESA Hubble Space Telescope. The gravitational influence of a suspected Jupiter-sized planet in the foreground may have catapulted the comets into the star.

This star, called HD 172555, represents the third extrasolar system where astronomers have detected doomed, wayward comets. The star resides 95 light-years from Earth.

Credit:
NASA/ESA and The Hubble Heritage Team (STScI/AURA)

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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 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.

Credit:
NASA/ESA and The Hubble Heritage Team (STScI/AURA)