Asteroid with Rings?

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from The Wall Street Journal,

Discovery of Dwarf Planet, Non-Planetary Rings Challenge Theories on Solar System.

Scientists added two discoveries to the inventory of celestial real estate in the solar system: a dwarf planet found far beyond Pluto’s orbit, and a set of rings, like those around Saturn, that encircle a distant asteroid.

Together, the finds are spurring astronomers to rethink theories about the forces at work beyond the known planets, where millions of comets, rocks and jagged blocks of ice are suspended in vast fields of space rubble.

The findings were reported Wednesday in the journal Nature.

The pinkish miniplanet, cataloged as 2012-VP113, is about 280 miles in diameter, a little more than the distance from New York to Washington, D.C. It is located about 80 times as far from the sun as is Earth, and is most likely is made of methane and water frozen around a rocky core.

It is the second dwarf planet to turn up in a region called the inner Oort cloud, where many comets are thought to originate. The first, called Sedna, was found in 2003.

The scientists believe that these two have many neighbors yet to be identified, created from sprays of ice and gravel pulled into place by passing stars, or yanked into position by as-yet-unknown rogue planets. They may all have been planets that once circled other stars, the scientists said.

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