Before you ask: No, the new dwarf planet discovered at the outskirts of our Sun’s sphere of influence will not be added to our list of local planets. Pluto, the famously scorned former cap to our solar system’s planetary members, is actually more than five times the size of this new satellite.
It orbits more than twice as far from the Sun as Pluto, and takes more than 15 times as long (4,340 years to be exact) to complete an orbital loop. It is also, however, bigger and more unique than a simple asteroid — and its orbit is interesting for more than just its size.
Still, that size is indeed unusual. The dwarf planet Sedna is the only comparable object known, with a similarly lonely orbit far beyond that of Neptune. Both Sedna and this new body, dubbed 2012 VP113 are considered to be part of the innermost portion of the Oort Cloud, a hypothesized sphere of small, icy “planetesimal” bodies that surrounds our solar system about 50,000 times further than the distance from the Earth to the Sun (called an astronomical unit, or AU).
VP113′s highly elliptical orbit takes it from about 80 to over 400 AU, which makes it very far out but still part of the far interior of the Oort Cloud.