A dwarf planet has been discovered far beyond the orbit of Pluto by astronomers from the Carnegie Science Institute. Researchers found the planet in 2015, but it took several years to determine its orbit. The planet is currently 80 AU’s (astronomical units, the mean distance between the Earth and Sun) or 12,000,000,000 km (7,500,000,000 miles) from our parent star.
Nicknamed Goblin, the dwarf planet (whose technical name is 2015 TG387) received its moniker from the designation TG (The Goblin), and the fact the body was discovered near Halloween 2015.
“The discovery of the 300-kilometer-wide planet was a lucky one. For 99% of its orbit, it would have been too faint to see, but astronomers caught it—using the Subaru 8-meter telescope in Hawaii—as it moved toward its closest approach to the sun,” researchers reported in Science Magazine.
Calculations suggest 2015 TG387 takes approximately 40,000 years to orbit once around our Sun. This places it within the inner Oort Cloud, a collection of bodies, including the dwarf planet Sedna, which encircle our Solar System beyond the furthest-known planet, Neptune. At the most-distant point in its orbit, Goblin travels out to 2,300 AU’s from the Sun, nearly 29 times further than its current position. At its closest approach to the Sun, this dwarf planet comes within 65 AU’s of our parent star.
“These so-called Inner Oort Cloud objects like 2015 TG387, 2012 VP113, and Sedna are isolated from most of the Solar System’s known mass, which makes them immensely interesting. They can be used as probes to understand what is happening at the edge of our Solar System,” said Scott Shepard of the Carnegie Institute, one of the people who discovered the distant world.
Other dwarf planets have been found beyond the orbit of Neptune, and like Goblin, variations in their orbits suggest another, larger, world – a so-called Planet X – may be hiding in the depths of the Solar System. Computer simulations show that Goblin has been in a stable orbit since the birth of the Solar System, and that orbit has likely been kept steady by the gravitational influence of a so-far-unseen ninth planet. Although this is not proof that such a world exists, it does lend additional evidence that Planet X is floating somewhere out there, in the depths of the Solar System.