List of trans-Neptunian objects

Compilation of 15 imaged trans-Neptunian objects. The first image compares some of the largest TNOs in terms of size, color and albedo.

This is a list of trans-Neptunian objects (TNOs), which are minor planets in the Solar System that orbit the Sun at a greater distance on average than Neptune, that is, their orbit has a semi-major axis greater than 30.1 astronomical units (AU). The Kuiper belt, scattered disk, and Oort cloud are three conventional divisions of this volume of space.^{[1][nb 1]} As of October 2018, the catalog of minor planets contains 528 numbered TNOs. In addition, there are more than 2,000 unnumbered TNOs, first observed between 1993 and 2018.^[3][4][5]

This list consists of all types of TNO subgroups: classical Kuiper belt object, also known as "cubewanos", scattered disc objects (SDOs) and detached objects including ESDO and EDDO, respectively, as well as sednoids. The list also contains several centaurs, if the object's orbit has a sufficiently large semi-major axis (a). Centaurs have unstable orbits in which the closest approach to the Sun (perihelion, q) is well inside of Neptune's orbit but the farthest point (Q) is very distant. Extreme trans-Neptunian objects (ETNOs) have a semi-major axis greater than 150 AU and perihelion greater than 30 AU.^[6]

The first TNO to be discovered was Pluto in 1930. It became the namesake of a larger group of resonant trans-Neptunian objects called "plutinos" (another resonant group are the "twotinos"). It took more than 60 years to discover a second TNO, Albion (provisionally known as 1992 QB₁), in 1992. The largest known trans-Neptunian objects are Pluto and Eris, followed by 2007 OR₁₀, Makemake, and Haumea. Most TNOs have low albedos typically around 0.09. Their color varies from blue-grey to very red (classes BB, BR, IR and RR). The following list also gives an object's full designation, mean-diameter (D), and discovery circumstances (date, discoverer and discovery site), as well as its orbital inclination (i) and eccentricity (e).

List

This list includes all numbered trans-Neptunian objects with a semi-major axis greater than 30.1 astronomical units (AU), Neptune's average orbital distance from the Sun. The data is sourced from MPC's "List of Trans Neptunian Objects" and "List Of Centaurs and Scattered-Disk Objects", completed with remarks and information from Johnston's Archive (diameter, class, binary, albedo, taxonomy and color).^[3][4][5]