Adapted from Carnegie Institution of Science press release, March 26, 2014:
A new distant dwarf planet, called 2012 VP113, has been discovered beyond the known edge of the Solar System. It is likely one of thousands of distant objects that are thought to form the so-called inner Oort cloud (see Section 8.2, p. 202). The findings were published March 27 in the journal Nature.
The known Solar System can be divided into three parts: the rocky planets like Earth, which are close to the Sun; the gas giant planets, which are further out; and the frozen objects of the Kuiper belt, which lie just beyond Neptune’s orbit. Beyond this, there appears to be an edge to the Solar System where only one object, Sedna, was previously known to exist for its entire orbit. But the newly found 2012 VP113 has an orbit that beyond Sedna’s, making it the furthest known in the solar system. The discovery of 2012 VP113 shows us that Sedna is not unique and is likely the second known member of the hypothesized inner Oort cloud, the likely origin of some comets.
2012 VP113’s closest orbit point to the Sun brings it to about 80 times the distance of the Earth from the Sun (80 AU). The Kuiper belt (composed of thousands of icy objects, including Pluto) ranges from 30 to 50 AU. The Solar System has a distinct edge at 50 AU – prior to this discovery, Sedna was the only object known to stay significantly beyond this outer boundary at 76 AU for its entire orbit.