A trans-Neptunian object (TNO), also written transneptunian object, is any minor planet in the Solar System that orbits the Sun at a greater average distance than Neptune, which has an orbital semi-major axis of 30.1 astronomical units (au).
Haumea is a dwarf planet located beyond Neptune's orbit. It was discovered in 2004 by a team headed by Mike Brown of Caltech at the Palomar Observatory in the United States and disputably also in 2005 by a team headed by José Luis Ortiz Moreno at the Sierra Nevada Observatory in Spain. On September 17, 2008, it was named after Haumea, the Hawaiian goddess of childbirth, under the expectation by the International Astronomical Union (IAU) that it would prove to be a dwarf planet. Nominal estimates make it the third-largest known trans-Neptunian object, after Eris and Pluto, and approximately the size of Uranus's moon Titania.
Makemake is a dwarf planet and the second-largest of what are known as the classical population of Kuiper belt objects, with a diameter approximately that of Saturn's moon Iapetus, or 60% that of Pluto. It has one known satellite. Its extremely low average temperature, about 40 K (−230 °C), means its surface is covered with methane, ethane, and possibly nitrogen ices.
(15874) 1996 TL66 (provisional designation 1996 TL66) is a trans-Neptunian object of the scattered disc orbiting in the outermost region of the Solar System.
19521 Chaos is a cubewano, a Kuiper-belt object not in resonance with any planet. Chaos was discovered in 1998 by the Deep Ecliptic Survey with Kitt Peak's 4 m telescope. Its albedo is 0.050+0.030
−0.016, making it, with its absolute magnitude (H) of 4.8, equivalent to a single spherical body 600+140
−130 km in diameter.
(55565) 2002 AW197 (provisional designation 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.
(612911) 2004 XR190, nicknamed Buffy, is a trans-Neptunian object, classified as both a scattered disc object and a detached object, located in the outermost region of the Solar System. It was first observed on 11 December 2004, by astronomers with the Canada–France Ecliptic Plane Survey at the Mauna Kea Observatories, Hawaii, United States. It is the largest known highly inclined (> 45°) object. With a perihelion of 51 AU, it belongs to a small and poorly understood group of very distant objects with moderate eccentricities.
(55636) 2002 TX300 is a bright Kuiper belt object in the outer Solar System estimated to be about 286 kilometres (178 mi) in diameter. It is a large member of the Haumea family that was discovered on 15 October 2002 by the Near-Earth Asteroid Tracking (NEAT) program.
(145452) 2005 RN43 (provisional designation 2005 RN43) is a classical Kuiper belt object. It has an estimated diameter of 679+55
−73 km. It was discovered by Andrew Becker, Andrew Puckett and Jeremy Kubica on 10 September 2005 at Apache Point Observatory in Sunspot, New Mexico. Brown estimates that it is possibly a dwarf planet.
(469372) 2001 QF298, provisionally known as 2001 QF298, is a resonant trans-Neptunian object that resides in the Kuiper belt in the outermost region of the Solar System. It was discovered on August 19, 2001 by Marc W. Buie. 2001 QF298 is a plutino, meaning that it is locked in a 3:2 orbital resonance with Neptune, much like Pluto.
(24835) 1995 SM55 (provisional designation 1995 SM55) is a trans-Neptunian object and member of the Haumea family that resides in the Kuiper belt, located in the outermost region of the Solar System. It was discovered on 19 September 1995, by American astronomer Nichole Danzl of the Spacewatch program at Kitt Peak National Observatory near Tucson, Arizona, in the United States. It measures approximately 200 kilometers in diameter and was the second-brightest known object in the Kuiper belt, after Pluto, until 1996 TO66 was discovered.
(35671) 1998 SN165 (provisional designation 1998 SN165) is a trans-Neptunian object from the Kuiper belt located in the outermost region of the Solar System. It was discovered on 23 September 1998, by American astronomer Arianna Gleason at the Kitt Peak National Observatory near Tucson, Arizona. The cold classical Kuiper belt object is a dwarf planet candidate, as it measures approximately 400 kilometers (250 miles) in diameter. It has a grey-blue color (BB) and a rotation period of 8.8 hours. As of 2021, it has not been named.
(86047) 1999 OY3 (provisional designation 1999 OY3) is a trans-Neptunian object that resides in the Kuiper belt beyond Pluto. It was discovered on July 18, 1999, at the Mauna Kea Observatory, Hawaii, USA.
The Haumea or Haumean family is the only identified trans-Neptunian collisional family; that is, the only group of trans-Neptunian objects (TNOs) with similar orbital parameters and spectra that suggest they originated in the disruptive impact of a progenitor body. Calculations indicate that it is probably the only trans-Neptunian collisional family. Members are known as Haumeids.
Gonggong is a dwarf planet, a member of the scattered disc beyond Neptune. It has a highly eccentric and inclined orbit during which it ranges from 34–101 astronomical units from the Sun. As of 2019, its distance from the Sun is 88 AU, and it is the sixth-farthest known Solar System object. According to the Deep Ecliptic Survey, Gonggong is in a 3:10 orbital resonance with Neptune, in which it completes three orbits around the Sun for every ten orbits completed by Neptune. Gonggong was discovered in July 2007 by American astronomers Megan Schwamb, Michael Brown, and David Rabinowitz at the Palomar Observatory, and the discovery was announced in January 2009.
(308193) 2005 CB79 is a trans-Neptunian object that is a member of the Haumea family.
2010 KZ39 is a trans-Neptunian object orbiting the Sun as a detached object in the outer reaches of the Solar System. The object was first observed on 21 May 2010 by astronomers Andrzej Udalski, Scott Sheppard, M. Szymanski and Chad Trujillo at the Las Campañas Observatory in Chile.
(523639) 2010 RE64 (provisional designation 2010 RE64) is a trans-Neptunian object in the scattered disc located in the outermost region of the Solar System, approximately 570 kilometers (350 miles) in diameter. It was discovered on 11 July 2010 by the Pan-STARRS-1 survey at the Haleakala Observatory, Hawaii, in the United States.
(532037) 2013 FY27 (provisional designation 2013 FY27) is a trans-Neptunian object and binary system that belongs to the scattered disc (like Eris). Its discovery was announced on 31 March 2014. It has an absolute magnitude (H) of 3.2. 2013 FY27 is a binary object, with two components approximately 740 kilometres (460 mi) and 190 kilometres (120 mi) in diameter. It is the ninth-intrinsically-brightest known trans-Neptunian object, and is approximately tied with 2002 AW197 and 2002 MS4 (to within measurement uncertainties) as the largest unnamed object in the Solar System.
