English subtitles for clip: File:Hubblecast 88.webm

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Images from ESO’s Very Large Telescope and the NASA/ESA Hubble Space Telescope

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have revealed unique and totally unexpected structures in the dusty disc around the star AU Microscopii.

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These fast-moving wave-like dust features are unlike anything ever observed, or even predicted, before now.

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AU Microscopii, or AU Mic for short, is a young nearby star surrounded by a large disc of dust.

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Studies of such discs can provide valuable clues about how planets form.

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Astronomers have been searching AU Mic’s disc for any signs of clumpy or warped features for years.

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Such features might give away the location of possible planets.

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For their search, astronomers have now used the powerful new imaging capabilities of

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ESO’s SPHERE instrument, mounted on the Very Large Telescope.

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And they discovered something completely unexpected.

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Five wave-like arches at different distances from the star showed up in the new image.

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The astronomers compared the SPHERE data with images of the disc taken by Hubble in 2010 and 2011.

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The comparison of the data showed that these ripples were moving — and moving very fast!

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At least three of the features are moving so fast that they are escaping from the gravitational pull of the star.

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Such high speeds rule out the possibility that these are conventional disc features

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caused by planets disturbing material in the disc while orbiting the star.

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There must have been something else involved to speed up the ripples and make them move so quickly.

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This means that they are a sign of something truly unusual.

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One explanation for the strange structure could be flares from the star.

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AU Mic often lets off huge bursts of energy from its surface.

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One of these flares could perhaps have violently stripped away

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material from one of the planets — if there are any planets.

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This material could now be propagating through the disc, propelled by the force of the flare.

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To get the final answer to the nature of these features

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astronomers will need additional observations made from the ground and from space.

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But, for now, these curious features remain a big surprise and an unsolved mystery.

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Transcribed by ESA/Hubble, Translated by ---