(55565) 2002 AW197 is a classical, non-resonant trans-Neptunian object from the Kuiper belt in the outermost region of the Solar System, also known as a cubewano. With a likely diameter of at least 700 kilometers (430 miles), it is approximately tied with 2002 MS4 and 2013 FY27 (to within measurement uncertainties) as the largest unnamed object in the Solar System. It was discovered at Palomar Observatory in 2002.
474640 Alicanto, provisionally designated 2004 VN112, is a detached extreme trans-Neptunian object. It was discovered on 6 November 2004, by American astronomer Andrew C. Becker at Cerro Tololo Inter-American Observatory in Chile. It never gets closer than 47 AU from the Sun (near the outer edge of the main Kuiper belt) and averages more than 300 AU from the Sun. Its large eccentricity strongly suggests that it was gravitationally scattered onto its current orbit. Because it is, like all detached objects, outside the current gravitational influence of Neptune, how it came to have this orbit cannot yet be explained. It was named after Alicanto, a nocturnal bird in Chilean mythology.
Detached objects are a dynamical class of minor planets in the outer reaches of the Solar System and belong to the broader family of trans-Neptunian objects (TNOs). These objects have orbits whose points of closest approach to the Sun (perihelion) are sufficiently distant from the gravitational influence of Neptune that they are only moderately affected by Neptune and the other known planets: This makes them appear to be "detached" from the rest of the Solar System, except for their attraction to the Sun.
(528219) 2008 KV42 (provisional designation:2008 KV42; nicknamed Drac) is a trans-Neptunian object and the first one with a retrograde orbit to be discovered. This retrograde motion with an orbital inclination of 103° suggests that it is the missing link between its source in the Hills cloud and Halley-type comets, thus providing further insight into the evolution of the outer Solar System. The object measures approximately 77 kilometers (48 miles) in diameter. With a semi-major axis of 42 AU, it takes about 269 years to complete an orbit around the Sun.
(612533) 2002 XV93, also written as 2002 XV93, is a trans-Neptunian object (TNO) with an absolute magnitude of 5.4. A 2:3 orbital resonance with Neptune makes it a plutino.
(445473) 2010 VZ98, provisional designation 2010 VZ98, is a trans-Neptunian object of the scattered disc, orbiting the Sun in the outermost region of the Solar System. It has a diameter of approximately 400 kilometers.
2012 DR30 is a trans-Neptunian object and centaur from the scattered disk and/or inner Oort cloud, located in the outermost region of the Solar System. The object with a highly eccentric orbit of 0.99 was first observed by astronomers with the Spacewatch program at Steward Observatory on 31 March 2009. It measures approximately 188 kilometers (120 miles) in diameter.
An extreme trans-Neptunian object (ETNO) is a trans-Neptunian object orbiting the Sun well beyond Neptune (30 AU) in the outermost region of the Solar System. An ETNO has a large semi-major axis of at least 150–250 AU. Its orbit is much less affected by the known giant planets than all other known trans-Neptunian objects. They may, however, be influenced by gravitational interactions with a hypothetical Planet Nine, shepherding these objects into similar types of orbits. The known ETNOs exhibit a highly statistically significant asymmetry between the distributions of object pairs with small ascending and descending nodal distances that might be indicative of a response to external perturbations.
2013 RF98 is a trans-Neptunian object. It was discovered on September 12, 2013, at Cerro Tololo-DECam.
2013 GP136 is a trans-Neptunian object from the scattered disc in the outermost reaches of the Solar System, approximately 212 kilometers in diameter. It was discovered on 8 February 2013, by the Outer Solar System Origins Survey at the Mauna Kea Observatories on the island of Hawaii, United States.
2014 FE72 is a trans-Neptunian object first observed on 26 March 2014, at Cerro Tololo Inter-American Observatory in La Serena, Chile. It is a possible dwarf planet, a member of the scattered disc, whose orbit extends into the inner Oort cloud. Discovered by Scott Sheppard and Chad Trujillo, the object's existence was revealed on 29 August 2016. Both the orbital period and aphelion distance of this object are well constrained. 2014 FE72 had the largest barycentric aphelion until 2018. However, the heliocentric aphelion of 2014 FE72 is second among trans-Neptunian objects (after the damocloid 2017 MB7). As of 2023, it is about 66 AU (9.9 billion km) from the Sun.
2015 KG163, also known as o5m52, is a trans-Neptunian object from the outermost region of the Solar System, approximately 102 kilometers (63 miles) in diameter. It was first observed on 24 May 2015, by astronomers of the Outer Solar System Origins Survey using the Canada–France–Hawaii Telescope at Mauna Kea Observatories, Hawaii, United States. With an observation arc of 2 years, it passed perihelion around August 2022 at a velocity of 6.5 km/s with respect to the Sun.
2005 RH52 is an extreme trans-Neptunian object from the extended scattered disc in the outermost region of the Solar System, approximately 130 kilometers (81 miles) in diameter. It was first observed on 3 September 2005, by astronomers with the Canada–France Ecliptic Plane Survey using the Canada–France–Hawaii Telescope at the Mauna Kea Observatories in Hawaii, United States.
(506479) 2003 HB57, is an extreme trans-Neptunian object of the extended scattered disc in the outermost region of the Solar System, approximately 180 kilometers in diameter. It was discovered by astronomers at the Mauna Kea Observatory on 26 April 2003.
2013 FS28 is an extreme trans-Neptunian object from the extended scattered disc on a highly eccentric orbit in the outermost region of the Solar System. It measures approximately 466 kilometers (290 miles) in diameter. The detached, extended scattered disc object belongs to the group of extreme trans-Neptunian objects. It was first observed on 16 March 2013, by American astronomers Scott Sheppard and Chad Trujillo at the Cerro Tololo Observatory in Chile.
(508338) 2015 SO20 is an extreme trans-Neptunian object and extended scattered disc object from the outermost region of the Solar System, approximately 220 kilometers (140 miles) in diameter.
2015 BP519, nicknamed Caju, is an extreme trans-Neptunian object from the scattered disc on a highly eccentric and inclined orbit in the outermost region of the Solar System. It was first observed on 17 January 2015, by astronomers with the Dark Energy Survey at Cerro Tololo Observatory (W84) in Chile. It has been described as an extended scattered disc object (ESDO), and fits into the group of extreme objects that led to the prediction of Planet Nine, and has the highest orbital inclination of any of these objects.
541132 Leleākūhonua, provisionally designated 2015 TG387, is an extreme trans-Neptunian object and sednoid in the outermost part of the Solar System. It was first observed on 13 October 2015, by astronomers at the Mauna Kea Observatories, Hawaii. Based on its discovery date near Halloween and the letters in its provisional designation 2015 TG387, the object was informally nicknamed "The Goblin" by its discoverers and later named Leleākūhonua, comparing its orbit to the flight of the Pacific golden plover. It was the third sednoid discovered, after Sedna and 2012 VP113, and measures around 220 kilometers (140 miles) in diameter.
The hypothetical Planet Nine would modify the orbits of extreme trans-Neptunian objects via a combination of effects. On very long timescales exchanges of angular momentum with Planet Nine cause the perihelia of anti-aligned objects to rise until their precession reverses direction, maintaining their anti-alignment, and later fall, returning them to their original orbits. On shorter timescales mean-motion resonances with Planet Nine provides phase protection, which stabilizes their orbits by slightly altering the objects' semi-major axes, keeping their orbits synchronized with Planet Nine's and preventing close approaches. The inclination of Planet Nine's orbit weakens this protection, resulting in a chaotic variation of semi-major axes as objects hop between resonances. The orbital poles of the objects circle that of the Solar System's Laplace plane, which at large semi-major axes is warped toward the plane of Planet Nine's orbit, causing their poles to be clustered toward one side.
2021 RR205 is an extreme trans-Neptunian object and sednoid discovered by astronomers Scott Sheppard, David Tholen, and Chad Trujillo with the Subaru Telescope at Mauna Kea Observatory on 5 September 2021. It resides beyond the outer extent of the Kuiper belt on a distant and highly eccentric orbit detached from Neptune's gravitational influence, with a large perihelion distance of 55.5 astronomical units (AU). Its large orbital semi-major axis (~1,000 AU) suggests it is potentially from the inner Oort cloud. Like 2013 SY99, 2021 RR205 lies in the 50–75 AU perihelion gap that separates the detached objects from the more distant sednoids; dynamical studies indicate that such objects in the inner edge this gap weakly experience "diffusion", or inward orbital migration due to minuscule perturbations by Neptune.
