A Second Sedna

Sedna, a dwarf planet that resides far out in the depths of the solar system, is the first known objects that belongs to the inner Oort cloud. Discovered in 2003, Sedna became a very important trans-Neptunian object, aiding in the quest to learn about the evolution of the Solar System. With a perihelion of 76 AU, Sedna was the farthest known body in the Solar System. Recently, an object called 2012VP113 was found to be another inner Oort cloud object. This confirms that Sedna is not an isolated body and that there may be more inner Oort cloud objects out there.

The authors conducted a sky survey that focused on objects with perihelion distances between 50 AU to around 300 AU. 2012VP113 was found to have a perihelion distance of 80 AU, making it farther away from the Sun than Sedna is. The surface color of 2012VP113 is moderately red, which is consistent with formation in the gas giant region, not in the classical Kuiper belt region.

An important question from the discoveries of Sedna and 2012VP113 is how do these inner Oort cloud objects form? Currently there are two preferred models, along with one lesser studied model. One model explores the possibility that a Kuiper belt object is perturbed by some planet-sized object out towards the inner Oort cloud region. The next model suggests that inner Oort cloud objects could have been created from a close stellar encounter during the formation of the early Solar System. The third model suggests that inner Oort cloud objects could be extrasolar planetesimals captured in the formation of the early Solar System. Each theory has different possibilities, and the discovery of additional inner Oort cloud objects would provide more insight into the formation of these bodies as well as our Solar System.

Image: A combination of three images showing 2012VP113, each taken two hours apart, on November 5, 2012. (Credit: Scott S. Sheppard/Carnegie Institution for Science)

Astronomers have recently announced the discovery of perhaps one of the most distant objects in our Solar System, a dwarf planet temporarily named 2012 VP113. Along with fellow dwarf planet Sedna, 2012 VP113 may be considered to be within the inner reaches of the Oort Cloud. The Oort Cloud, as recently discussed on the third episode of Cosmos: A Spacetime Odyssey, is a hypothesized sphere of large icy bodies, mostly planetesimals, that is thought to be the origin of comets before a slight gravitational tug from the Sun starts them on their journey inwards.

The discoveries of extremely distant bodies like 2012 VP113 are difficult because objects at such a distance from the Sun reflect very little light back to Earth. They also serve as a reminder of how little we know about what lies at the outer edges of our own Solar System. At the same time, studying these objects can be incredibly valuable as they may offer hints at the earliest stages of the Solar System when the Sun and planets were just beginning to form.

The image shows 2012 VP113’s movement (indicated by the arrow) as it was tracked over a four hour period.

Read more about the announcement here: http://goo.gl/oZ97qj

Watch Episode 3 of COSMOS: “When Knowledge Conquered Fear” for free on Hulu: http://bit.ly/COSMOS-Ep3