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This is a list of trans-Neptunian objects (TNO) in the Solar System, along with a list of their moons. A trans-Neptunian object is any minor planet in the Solar System that orbits the Sun at a greater distance on average than Neptune.
Contents
The first trans-Neptunian object to be discovered was Pluto in 1930. It took more than 60 years to discover, in 1992, a second trans-Neptunian object, (15760) 1992 QB1, with only the discovery of Pluto's moon Charon in 1978 before that. Now over 1200 trans-Neptunian objects appear on the Minor Planet Center's List Of Transneptunian Objects. As of November 2015, 270 of these have their orbits well-enough determined that they have been given a permanent minor planet designation.
The largest known trans-Neptunian objects are Pluto and Eris, followed by Makemake, 2007 OR10, and Haumea. The Kuiper belt, scattered disk, and Oort cloud are three conventional divisions of this volume of space, though treatments vary and a few objects such as Sedna do not fit easily into any division.
List
This list includes all numbered and several unnumbered trans-Neptunian objects (many unnumbered TNOs are not yet notable and are excluded). As TNOs are defined to orbit the Sun at a greater distance than Neptune (on average), they all have a semi-major axis greater than 30.103 astronomical unit (AU).
This list consists of all types of TNO subgroups: Kuiper belt objects, scattered disc objects, detached objects, and sednoids. Objects with trans-Neptunian orbits that have been classified as centaurs rather than "true" TNOs by some astronomers and institutions (notably the Deep Ecliptic Survey) have also been included. This population of objects has unstable orbits in which the closest approach to the Sun (perihelion) is well inside of Neptune's orbit but the farthest point (aphelion) is very distant; they accordingly travel across Neptune's orbit, the Kuiper belt, and sometimes the scattered disc, and are noted here with a location of "transient". An object with a semi-major axis greater than 150 AU and perihelion greater than 30 AU is known as an extreme trans-Neptunian object (ETNO).
Moons of trans-Neptunian objects
This is a partial list of the moons of TNOs.