Icy planetoid found lurking at edge of solar system

Newly discovered object is one of the most distant bodies orbiting the sun

WANDERING WORLD  The newly discovered planetoid, 2012 VP113, moves against a backdrop of stars in these pictures taken at the Cerro Tololo Inter-American Observatory in Chile.  This photo combines three images taken a couple of hours apart. The individual images of 2012 VP113 are colored red, green and blue.  It moved two-thousandths of a degree across the sky between the first and last image.

Scott S. Sheppard/Carnegie Institution for Science

There’s a new icy world in the outer suburbs of the solar system. Named 2012 VP113, astronomers think the planetoid could be a member of the Oort cloud, the giant icy junkyard thought to envelop the sun (SN: 10/19/13, p. 19).

The newly found object joins the dwarf planet Sedna as the only two worlds known to orbit beyond the Kuiper belt, where Pluto resides along with hordes of ice boulders left over from the formation of the solar system.

Astronomers discovered 2012 VP113 as a spot drifting against the fixed backdrop of stars in pictures of a patch of sky taken a couple of hours apart. Continued observations at Chile’s Cerro Tololo Inter-American Observatory and Las Campanas Observatory revealed a roughly 450-kilometer-wide planetoid that comes no closer to the sun than 12 billion kilometers — about 80 times farther than Earth.

Astronomers argue in the March 27 Nature that the presence of 2012 VP113 and Sedna hint at a vast unseen reservoir of icy worlds at the edge of the solar system. The two could also help researchers understand the solar system’s early development and interactions with its neighbors in the galaxy. 

Christopher Crockett is an Associate News Editor. He was formerly the astronomy writer from 2014 to 2017, and he has a Ph.D. in astronomy from the University of California, Los Angeles.

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