Trans Neptunian Object (TNO) is a minor planet or dwarf planet in the Solar System.
These are objects that orbit beyond the Sun’s orbit, Neptune.
Their semimajor axis is located at an average distance of 30.1 Astronomincal Unit (AU) from the Sun.
● Located as the Classical, Resonant objects, and Scattered Disc of the Kuiper Belt.
TNOs have also been further isolated from sednoids.
Based on data up to October 2020, 678 items in the Minor Planets catalog have been classified as TNO.
About 2,000 objects are yet to be verified.
Pluto, discovered in 1930, was the first trans-Neptuneian object. It took until 1992 to find the second trans-Neptunian object to orbit the Sun directly.It was 15760 Albion.
The largest known TNO is Eris, followed by Pluto, Haumea, Make make and Gonggong.
More than 80 moons have been found in the orbits of Trans Neptune objects.
TNOs vary in color, ranging from Gray-Blue (BB) or Very Red (RR).
It is generally believed that volatile ice, such as Rocks and Amorphus carbon, is composed of water and methane, which are coated with toholins and other organic compounds.
Semi major Axis 12 minor planets larger than 150 AU and Perihelion larger than 30 AU have been identified so far, known as Extreme Trans-Neptunian Objects (ETNOs).