Rings discovered around asteroid-like object
A team of astronomers at the National Observatory in Brazil have found a pair of rings around an asteroid orbiting between Saturn and Uranus named Chariklo. While not as dazzling as Saturn’s rings, it’s the first time rings have been discovered outside of the four gas giants — Jupiter, Saturn, Uranus and Neptune. How little Chariklo got its rings remains a mystery, but scientists think they may have formed from debris from a violent collision. Chariklo’s diameter is about 155 miles. By comparison, Lake Ontario is 192 miles long. The discovery was published Wednesday in the journal Nature.
— Associated Press
Astronomers searching for the faintest glimmers of light beyond distant Pluto say they’ve discovered a new dwarf planet — and that this planetoid’s movements hint that an invisible giant planet perhaps 10 times the size of Earth could be lurking around the dark fringes of our solar system.
The pink frozen world 7½ billion miles from the sun helps confirm the existence of an “inner Oort cloud,” a celestial wasteland that was once thought to be empty, and is the second such object to be discovered in the region.
Until now, the lone known resident in this part of the solar system was an oddball dwarf planet spotted in 2003 named Sedna.
The latest discovery shows “Sedna is not a freak. We can have confidence that there is a new population to explore,” Yale University senior research scientist David Rabinowitz said in an email. He was one of Sedna’s discoverers, but had no role in the new find detailed in today’s issue of the journal Nature.
For years, astronomers hunted in vain for other Sednas in the little-studied fringes of the solar system.
The new dwarf planet, 2012 VP113, was tracked using a new camera on a ground telescope in Chile by Scott Sheppard of the Carnegie Institution for Science in Washington, D.C., and Chad Trujillo of the Gemini Observatory in Hawaii.
The new planetoid is jokingly nicknamed “Biden” after Vice President Joe Biden because of the object’s initials. It measures about 280 miles across, or half the diameter of Sedna. It’s bone-chilling cold with a temperature of around minus-430 degrees Fahrenheit, and under observation appears more pink and much fainter, which made it hard to detect.
By contrast, Earth is about 7,900 miles across and located 93 million miles from the sun.
While the dwarf planet is incredibly far out, it’s still not far enough to be part of the Oort cloud, a hypothesized cloud of icy debris that surrounds the solar system’s disc in a spherical shell that stretches a mind-blowing 5,000 to 100,000 astronomical units from the sun. 2012 VP-113’s orbit stretches for a few hundred astronomical units, in what scientists thought was an empty doughnut ring of space between the Oort cloud and the Kuiper belt.
Sedna and VP reside in a region known as the inner Oort cloud in the outer edge of the solar system where some comets such as the sun-diving Comet ISON are thought to originate. ISON broke ap
art last year after brushing too close to the sun.
“Finding Sedna so far away seemed odd and potentially a fluke. But this one
is beginning to make it look like that might be a typical place for objects to be. Not at all what I would have guessed,” said Mike Brown, an astronomer at the California Institute of Technology.
Sheppard and Trujillo estimate there are probably thousands of similar objects in the inner Oort cloud.
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Not all of them will be visible to telescopes because they’re so far away and it takes a long time for them to swing by the sun. Sedna and VP were spotted at their closest approach to the sun, which allowed light from the sun to hit the objects and bounce back to observatories on Earth.
VP is currently the third farthest object in the solar system after dwarf planet Eris and Sedna, but it has an eccentric, elongated orbit that can take it out to 42 billion miles from the sun. Sedna can loop out as far as 84 billion miles from the sun at its farthest point.
Now that Sedna has company — and likely lots of them — scientists are searching for more objects in an effort to learn how they and the solar system formed and evolved.
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