A trans-Neptunian object (TNO), also written transneptunian object, is any minor planet in the Solar System that orbits
Typically, … See more

The orbit of each of the planets is slightly affected by the gravitational influences of the other planets. Discrepancies in the early 1900s between the observed and expected orbits of Uranus and Neptune suggested that there … See more

According to their distance from the Sun and their orbital parameters, TNOs are classified in two large groups: the Kuiper belt objects (KBOs) and the scattered disc objects (SDOs). The diagram to the right illustrates t… See more

Given the apparent magnitude (>20) of all but the biggest trans-Neptunian objects, the physical studies are limited to the following:
• thermal emissions for the largest objects (see size determination)
• colour indices, i.e. comparison… See more

The only mission to date that primarily targeted a trans-Neptunian object was NASA's New Horizons, which was launched in January 2006 and flew by the Pluto system in July 2015 and 486958 Arrokoth in January 20… See more

Among the extreme trans-Neptunian objects are three high-perihelion objects classified as sednoids: 90377 Sedna, 2012 VP113, and 541132 Leleākūhonua. They are distant detached objects with perihelia greater tha… See more

• Dwarf planet
• Mesoplanet
• Nemesis (hypothetical star)
• Planet Nine
• Sednoid… See more