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Asteroid 2867 Steins seen by Rosetta
Publiée le 2010-01-18 |
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The ESA spacecraft Rosetta en route to the comet 67P/Churyumov-Greasimenko approached on September 5, 2008 a small main belt asteroid of 4.6 km across, 2867 Steins. Images taken by the onboard camera OSIRIS show an asteroid resembling a cut diamond. Its surface is covered by shallow craters. A string of 7 small craters identical, regularly spaced, adorns one of the facets of the asteroid.
The shape is probably due to an effect of resurfacing due to the YORP effect. This effect is due to asymmetrical reradiating of solar radiation by any body of irregular shape. A particularly imposing equatorial bulge contributes to the appearance of diamond. YORP spin-up could have caused landsliding of mid-latitude surface material towards the equatorial bulge.
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