Telescope spies water plumes on dwarf planet Ceres - 0 views
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Scientists
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have made the first definitive detection of water vapor on the largest and roundest object in the asteroid belt, Ceres.
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Plumes of water vapor are thought to shoot up periodically from Ceres when portions of its icy surface warm slightly
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Ceres is classified as a dwarf planet, a solar system body bigger than an asteroid and smaller than a planet.
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"This is the first time water vapor has been unequivocally detected on Ceres or any other object in the asteroid belt and provides proof that Ceres has an icy surface and an atmosphere,"
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Michael Küppers of ESA in Spain
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NASA's Dawn mission, which is on its way to Ceres now after spending more than a year orbiting the large asteroid Vesta
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Dawn is scheduled to arrive at Ceres in the spring of 2015, where it will take the closest look ever at its surface.
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will map the geology and chemistry of the surface in high resolution
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International Astronomical Union, the governing organization responsible for naming planetary objects
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Ceres was known as the largest asteroid in our solar system
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reclassified Ceres as a dwarf planet because of its large size. It is roughly 590 miles (950 kilometers) in diameter
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When it first was spotted in 1801, astronomers thought it was a planet orbiting between Mars and Jupiter
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Scientists believe Ceres contains rock in its interior with a thick mantle of ice that, if melted, would amount to more fresh water than is present on all of Earth
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The materials making up Ceres likely date from the first few million years of our solar system's existence and accumulated before the planets formed.
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Until now, ice had been theorized to exist on Ceres but had not been detected conclusively
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far-infrared vision to see, finally, a clear spectral signature of the water vapor. But
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did not see water vapor every time it looked
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spied water vapor four different times, on one occasion there was no signature.
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what scientists think is happening
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when Ceres swings through the part of its orbit that is closer to the sun, a portion of its icy surface becomes warm enough to cause water vapor to escape in plumes
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a rate of about 6 kilograms (13 pounds) per second
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When Ceres is in the colder part of its orbit, no water escapes
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The strength of the signal also varied over hours, weeks and months
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water vapor plumes rotating in and out of Herschel's views as the object spun on its axis
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This enabled the scientists to localize the source of water to two darker spots on the surface of Ceres
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previously seen by NASA's Hubble Space Telescope and ground-based telescopes. The dark spots might be more likely to outgas because dark material warms faster than light material.
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"The lines are becoming more and more blurred between comets and asteroids," said Seungwon Lee of JPL
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Paul von Allmen, also of JPL. "We knew before about main belt asteroids that show comet-like activity, but this is the first detection of water vapor in an asteroid-like object."