Scientists using ground-based observatories have discovered an object that is believed to have one of the most distant orbit found beyond the known edge of our solar system. Named 2012 VP113, it may be a dwarf planet. A dwarf planet is an object in orbit around the sun that is large enough to have its own gravity pull itself into a nearly round or spherical shape.
The discovery shows the outer reaches of our solar system are not an empty wasteland as once was thought. There may be many more inner Oort Cloud bodies awaiting discovery.
2012 VP113's closest orbit point to the sun brings it to about 80 times the distance of the Earth from the sun, a measurement referred to as an astronomical unit or AU. The rocky planets and asteroids exist at distances ranging between .39 and 4.2 AU. Gas giants are found between 5 and 30 AU, and the Kuiper Belt (composed of hundreds of thousands of icy objects, including Pluto) ranges from 30 to 50 AU. In our solar system there is a distinct edge at 50 AU. Until 2012 VP113 was discovered, only Sedna, with a closest approach to the Sun of 76 AU, was known to stay significantly beyond this outer boundary for its entire orbit.
Measurements of the color of 2012 VP113 show it is moderately red. This is typical of objects in the Kuiper Belt and suggests that 2012 VP113 formed in the gas giant region of the solar system before being ejected to the inner Oort Cloud. Assuming that 2012 VP113 reflects 15 percent of the light falling on it, it is about 450 km (280 miles) in diameter.
Our known solar system consists of 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, the solar system thins out. There was only one object somewhat smaller than Pluto, Sedna, previously known to inhabit this outer zone for its entire orbit. But 2012 VP113 has an orbit that keeps it even more distant from the Sun than Sedna is at its closest.
Sedna was discovered beyond the Kuiper Belt edge in 2003. It was not known if Sedna was unique, as Pluto was once thought to be before the Kuiper Belt was discovered in 1992. The discovery of 2012 VP113 proves Sedna is not unique. 2012 VP113 is likely the second known member of the hypothesized inner Oort Cloud. The inner Oort Cloud is gravitationally more stable than the outer Oort Cloud, which is likely where some comets originate.
Scientists believe that about 900 objects with orbits like Sedna and 2012 VP113 with sizes larger than 1,000 km (621 miles) may exist. The small worlds are likely one of hundreds of thousands of distant objects that inhabit the region in our solar system scientists refer to as the inner Oort cloud. The total population of the inner Oort cloud is likely bigger than that of the Kuiper Belt and main asteroid belt.
Some of the inner Oort Cloud objects could rival the size of Mars or even Earth, but inner Oort Cloud objects are so distant that even very large ones would be too faint to detect with current technology.
Both Sedna and 2012 VP113 were found near their closest approach to the sun, but they both have orbits that go out to hundreds of AU, at which point they would be too faint to discover. The similarity in the orbits found for Sedna, 2012 VP113 and a few other objects near the edge of the Kuiper Belt suggests that Sedna's and new object's orbits might be influenced by the potential presence of a yet unseen planet perhaps up to 10 times the size of Earth.
Further studies of this deep space arena will continue.
2012 VP113 was first observed on 5 November 2012 by Chadwick Trujillo of the Gemini Observatory in Hawaii and Scott Sheppard of the Carnegie Institution in Washington. They used the National Optical Astronomy Observatory's 4 meter (13 foot) telescope in Chile to discover 2012 VP113. The Magellan 6.5 meter (21 foot) telescope at Carnegie's Las Campanas Observatory in Chile was used to determine the orbit of 2012 VP113 and obtain detailed information about its surface properties.
How 012 VP113 Got its Name:
The leading four digits of this provisional designation give the year of discovery. "V" indicates the discovery was in the first half-month of November. "P113" means that the letter P being used for 114th time in this half-month for a provisional designation and that this object is the 2,840th object discovered from Nov. 1-15, 2012. The object was nicknamed "Biden" after the current Vice President Joseph Biden because of the VP in its initial designation. This small body will later be named officially by the International Astronomical Union.