Discovery [1] [2] | |
---|---|
Discovered by | D. J. Tholen S. S. Sheppard C. W. Trujillo |
Discovery site | Mauna Kea Obs. |
Discovery date | 13 October 2015 (first observed only) |
Designations | |
2015 TH367 | |
V774104 (internal designation) | |
TNO [3] · SDO [4] distant [1] | |
Orbital characteristics [3] | |
Epoch 2015-Dec-05 (JD 2457361.5) | |
Uncertainty parameter 8 | |
Observation arc | 2.1 years using 10 observations |
Aphelion | 128±18 AU [a] |
Perihelion | 29.3±1.2 AU |
78±11 AU | |
Eccentricity | 0.63±0.07 |
695±150 yr [a] | |
66° ±22° | |
0° 0m 4.716s / day | |
Inclination | 10.99°±0.025° [b] |
245.1°±0.06° | |
≈1888±15? [5] | |
17°±7° | |
Neptune MOID | ≈0.5 AU (75 million km) [1] |
Physical characteristics | |
211 km(estimate) [6] 220 km(est. at 0.09) [7] | |
0.08 (assumed) [6] | |
26.2 [2] | |
6.6 [3] [1] | |
2015 TH367 is a trans-Neptunian object approximately 220 kilometers (140 miles) in diameter. As of 2021 [update] it is approximately 90 AU (13 billion km) from the Sun. [8] At the time of its announcement in March 2018, it was the third most distant observed natural object in the Solar System, after Eris and 2014 UZ224 . [c]
At a visual apparent magnitude of 26.2, it is one of the faintest trans-Neptunian objects observed and only the largest telescopes in the world can observe it. Being so far from the Sun, 2015 TH367 moves very slowly among the background stars and has only been observed eight times over 355 days. [3] It requires an observation arc of several years to refine the uncertainties in the approximately 700-year orbital period and determine whether it is currently near or at aphelion (farthest distance from the Sun). As of 2023 the nominal JPL Horizons solution has it coming to aphelion around the year 2238, [9] whereas Project Pluto (which only fit 5 of the 8 observations) shows it reached aphelion around 2015. [10]
2015 TH367 was first observed by Scott Sheppard, Chad Trujillo, and David Tholen on 13 October 2015 using the Subaru Telescope, a large reflecting telescope at the Mauna Kea Observatories on the summit of Mauna Kea with a primary mirror 8.2 meters (27 ft) in diameter. [2] In 2015 it was only observed for 26 days, [2] which is a very short observation arc for a trans-Neptunian object as objects far from the Sun move very slowly across the sky. It is calculated that it will remain in the constellation of Aries from 1994 until 2077. It was announced on 13 March 2018 alongside several other trans-Neptunian objects with a current heliocentric distance greater than 50 AU. [11] The trans-Neptunian objects 541132 Leleākūhonua and 2015 TJ367 were also discovered by this team on 13 October 2015.
The orbit of 2015 TH367 is poorly constrained, as it has only been observed 10 times over 2 years due to how dim it is. [3] At a visual apparent magnitude of 26.2, [2] it is about 75 million times fainter than what can be seen with the naked eye, [d] and it is one of the dimmest trans-Neptunian objects ever observed, only being able to be seen by the largest modern telescopes. The JPL Small-Body Database estimates that it came to perihelion (closest approach to the Sun) around the year 1888±15. [3] JPL estimates aphelion (farthest distance from the Sun) to be in 2238 at 128 AU [9] whereas Project Pluto (which only fit 5 of the 8 observations) estimates aphelion was in 2015 at 86 AU. [10] As the JPL solution fits all 8 observations, it is a better orbit determination. When dealing with statistics of small numbers, automation can reject some data unnecessarily.
The precise distance of 2015 TH367 still remains unknown due to its poorly understood orbit and the fact it has not been observed since 2016. [1] It is currently outbound roughly 90±4 AU from the Sun, [8] and will require further observations to better refine the orbit. At magnitude 26, it is only observable with a small number of telescopes that are capable of following it up and refining its orbit. It is expected to come to opposition in the constellation of Aries around 3 November 2021 when it should have a solar elongation of roughly 175°.
As of February 2021 [update] , there are only five known minor planets further from the Sun than 2015 TH367 under its nominal orbit: Eris (95.9 AU), 2020 FA31 (97.2 AU), 2020 FY30 (99.0 AU), 2018 VG18 (123.5 AU), and 2018 AG37 (~132 AU). [12] [13]
Observed Solar System objects that periodically become more distant than 89 AU from the Sun include Sedna (which is much larger in size), 2000 CR105 , 2012 DR30 , 2013 BL76 , and 2005 VX3 . There are 804 known objects that have aphelia more than 89 AU from the Sun as of March 2018. [14] This distance is about double the outer limit of the torus-shaped Kuiper belt that lies outside Neptune's orbit. Far beyond this region is the vast spherical Oort cloud enshrouding the Solar System, whose presence was deduced from the orbits of long-period comets.
Another distant object publicly known as V774104 was purportedly discovered at around 103 AU on 13 October 2015 by the same team, but public press releases may have confused its distance with Leleākūhonua (V302126, then known as 2015 TG387). [15] [16] 2015 TH367 is believed to be V774104.
Study of the population of Solar System objects that are significantly more distant than 2015 TH367 will likely require new instruments. The proposed Whipple spacecraft mission is designed to determine the outer limit of the Kuiper belt and directly detect Oort cloud objects out to 10,000 AU. Such objects are too small to detect with current telescopes except during stellar occultations. The proposal involves use of a wide field of view and rapid recording cadence to allow detection of many such events. [17]
Sedna is a dwarf planet in the outermost reaches of the Solar System, orbiting the Sun beyond the orbit of Neptune. Discovered in 2003, the planetoid's surface is one of the reddest known among Solar System bodies. Spectroscopy has revealed Sedna's surface to be mostly a mixture of the solid ices of water, methane, and nitrogen, along with widespread deposits of reddish-colored tholins, a chemical makeup similar to those of some other trans-Neptunian objects. Within the range of uncertainties, it is tied with the dwarf planet Ceres in the asteroid belt as the largest dwarf planet not known to have a moon. Its diameter is roughly 1,000 km. Owing to its lack of known moons, the Keplerian laws of planetary motion cannot be employed for determining its mass, and the precise figure remains as yet unknown.
(612911) 2004 XR190, informally 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.
1995 GJ might be a trans-Neptunian object and/or high-inclination cubewano from the Kuiper belt in the outermost region of the Solar System, and based on the calculated distance and brightness is assumed to be approximately 175 kilometers in diameter. It is a lost minor planet that has only been observed six times on the nights of 3–4 April 1995, by David Jewitt and Jun Chen at the Mauna Kea Observatory, Hawaii, using the UH88 telescope, and has not been observed ever since. The object is estimated to have been discovered right at perihelion at a distance of 39±1900 AU from the Sun. On the night of discovery, the object is estimated to have been moving away from Earth at 16 km/s with the uncertainty in the velocity being an unrealistic ±238000 km/s.
(308933) 2006 SQ372 is a trans-Neptunian object and highly eccentric centaur on a cometary-like orbit in the outer region of the Solar System, approximately 123 kilometers (76 miles) in diameter. It was discovered through the Sloan Digital Sky Survey by astronomers Andrew Becker, Andrew Puckett and Jeremy Kubica on images first taken on 27 September 2006 (with precovery images dated to 13 September 2005).
(523622) 2007 TG422 (provisional designation 2007 TG422) is a trans-Neptunian object on a highly eccentric orbit in the scattered disc region at the edge of Solar System. Approximately 260 kilometers (160 miles) in diameter, it was discovered on 3 October 2007 by astronomers Andrew Becker, Andrew Puckett and Jeremy Kubica during the Sloan Digital Sky Survey at Apache Point Observatory in New Mexico, United States. According to American astronomer Michael Brown, the bluish object is "possibly" a dwarf planet. It belongs to a group of objects studied in 2014, which led to the proposition of the hypothetical Planet Nine.
2010 GB174 is a detached object, discovered on 12 April 2010 on data taken at the Canada France Hawaii Telescope as part of the Next Generation Virgo Cluster Survey. It never gets closer than 48.5 AU from the Sun (about the outer edge of the Kuiper belt). Its large eccentricity strongly suggests that it was gravitationally scattered onto its current orbit. It is, like all detached objects, outside the current influence of Neptune, so how it got its current orbit is unknown. 2010 GB174 has the third highest Tisserand parameter relative to Jupiter of any Trans-Neptunian object, after Sedna and 2012 VP113. It has not been observed since 2015. It comes to opposition in late March each year in the constellation of Virgo.
(668643) 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.
2005 VX3 is trans-Neptunian object and retrograde damocloid on a highly eccentric, cometary-like orbit. It was first observed on 1 November 2005, by astronomers with the Mount Lemmon Survey at the Mount Lemmon Observatory in Arizona, United States. The unusual object measures approximately 7 kilometers (4 miles) in diameter. It has the 3rd largest known heliocentric semi-major axis and aphelion. Additionally its perihelion lies within the orbit of Jupiter, which means it also has the largest orbital eccentricity of any known minor planet.
2012 VP113 is a trans-Neptunian object of the sednoid population, located in the outermost reaches of the Solar System. It was first observed on 5 November 2012 by American astronomers Scott Sheppard and Chad Trujillo at the Cerro Tololo Inter-American Observatory in Chile. The discovery was announced on 26 March 2014. The object probably measures somewhere between 300 and 1000 km in diameter, possibly large enough to be a dwarf planet.
A sednoid is a trans-Neptunian object with a large semi-major axis and a high perihelion, similar to the orbit of the dwarf planet Sedna. The consensus among astronomers is that there are only three objects that are known from this population: Sedna, 2012 VP113, and 541132 Leleākūhonua (2015 TG387). All three have perihelia greater than 60 AU. These objects lie outside an apparently nearly empty gap in the Solar System and have no significant interaction with the planets. They are usually grouped with the detached objects. Some astronomers consider the sednoids to be Inner Oort Cloud (IOC) objects, though the inner Oort cloud, or Hills cloud, was originally predicted to lie beyond 2,000 AU, beyond the aphelia of the three known sednoids.
2013 RF98 is a trans-Neptunian object. It was discovered on September 12, 2013, at Cerro Tololo-DECam.
(674118) 2015 KH162 is a large trans-Neptunian object orbiting in the scattered disc region of the outermost Solar System. First observed in 2015, this minor planet is one of the most distant objects from the Sun at 60.6 AU, or twice as far as Neptune.
(523794) 2015 RR245, provisional designation 2015 RR245, is a large trans-Neptunian object of the Kuiper belt in the outermost regions of the Solar System. It was discovered on 9 September 2015, by the Outer Solar System Origins Survey at Mauna Kea Observatories on the Big island of Hawaii, in the United States. The object is in a rare 2:9 resonance with Neptune and measures approximately 600 kilometers in diameter. 2015 RR245 was suspected to have a satellite according to a study announced by Noyelles et al. in a European Planetary Science Congress meeting in 2019.
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.
2017 MB7 is a trans-Neptunian object and damocloid on a cometary-like orbit from the outer Solar System, approximately 6 kilometers (4 miles) in diameter. It was first observed on 22 June 2017 by the Pan-STARRS survey at Haleakala Observatory in Hawaii, United States. This unusual object has the largest heliocentric aphelion, semi-major axis, orbital eccentricity and orbital period of any known periodic minor planet, even larger than that of 2010 LN135 and 2014 FE72; it is calculated to reach several thousand AU (Earth-Sun) distances at the farthest extent of its orbit.
541132 Leleākūhonua (provisional designation 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.
2018 VG18 is a distant trans-Neptunian object (TNO) that was discovered when it was 123 AU (18 billion km; 11 billion mi) from the Sun, more than three times the average distance between the Sun and Pluto. It was discovered on 10 November 2018 by Scott Sheppard, David Tholen, and Chad Trujillo during their search for TNOs whose orbits might be gravitationally influenced by the hypothetical Planet Nine. They announced the discovery of 2018 VG18 on 17 December 2018 and nicknamed the object "Farout" to emphasize its distance from the Sun.
2018 AG37 is a distant trans-Neptunian object and centaur that was discovered 132.2 ± 1.5 AU (19.78 ± 0.22 billion km) from the Sun, farther than any other currently observable known object in the Solar System. Imaged in January 2018 during a search for the hypothetical Planet Nine, the confirmation of this object was announced in a press release in February 2021 by astronomers Scott Sheppard, David Tholen, and Chad Trujillo. The object was nicknamed "FarFarOut" to emphasize its distance from the Sun.
Objects with distance from Sun over 84.2 AU