There’s Another Dwarf Planet Out Past Pluto, And Maybe a Giant, Rocky One Too

2012 VP113 expands what we know about the odd region of the solar system known as the inner Oort cloud

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The newly discovered 2012 VP113, in red, and Sedna, in orange, orbit far from the Sun. The four pink bands are Jupiter, Saturn, Uranus and Neptune. The blue dots are Pluto and the rest of the Kuiper belt. Scott S. Sheppard: Carnegie Institution for Science

Far out past Pluto, more than 80 times the distance from the Sun to the Earth, there's an icy body that hints at hitherto unknown mysteries of the solar system. In a new study, researchers describe this newly discovered dwarf planet, an object tentatively known as 2012 VP113. But maybe as interesting as the planet itself is what its calculated orbit might represent.

Astronomers aren't allowed to give 2012 VP113 a better name yet, says the BBC—that will have to wait until more details on the new dwarf planet's orbit are hashed out. For the time being, they've come to call it either just “VP” or “Biden” for the U.S. Vice-President, says Alexandra Witze for Nature.

The new planet is small, cold and very, very far away. At just 280 miles across, the whole thing would fit between Chicago and St. Louis. It takes 4,600 years to orbit the Sun, says Sky and Telescope.

Photos of 2012 VP113 taken in November, 2012. (Scott S. Sheppard: Carnegie Institution for Science)

2012 VP113 joins Sedna, another distant dwarf discovered in 2003, as the second dwarf planet among the so-called “Inner Oort cloud objects”—bodies that orbit far, far beyond the range of the Kuiper belt, where Pluto, Makemake, Eris and a field of other small, orbiting objects reside.

Unlike the largely circular orbits of Earth, Jupiter and the solar system's other planets, the orbits of Sedna and 2012 VP113 are squashed and stretched. At its closest, VP is 7.4 billion miles from the Sun. At its furthest: 42 billion.

This is where this new discovery hints at another exciting possibility. These oblong orbits, astronomers suggest, may indicate the presence of an as-yet-unseen major planet far out in the Oort cloud. A rocky planet 10 times the size of Earth, orbiting some 250 times the distance from the Sun to the Earth, would provide enough of a tug to twist the inner Oort cloud objects' orbits, says New Scientist.

Mike Brown, the astronomer who helped find Sedna (and the man who drove a stake through the heart of Pluto's planetary status), however, is cautioning against getting too enthusiastic about the prospect of this potential Planet X. "It is possible that some undiscovered large object out there is doing this, but there are likely many other explanations, too, most of them sadly more mundane,” said Brown to New Scientist's Nicola Jenner.

Sign of a distant super-planet or not, VP is a clue that the solar system is much more full than we once thought. After finding Sedna and VP, astronomers are now estimating that as many as 900 other dwarf planets also fill the inner Oort cloud, says Stuart Clark for the Guardian.