Discovery [1] [2] | |
---|---|
Discovered by | |
Discovery site | Mauna Kea Obs. |
Discovery date | 7 June 2008 |
Designations | |
2008 LC18 | |
Orbital characteristics [1] | |
Epoch 4 September 2017 (JD 2458000.5) | |
Uncertainty parameter 5 | |
Observation arc | 4.12 yr (1,506 days) |
Aphelion | 32.445 AU |
Perihelion | 27.667 AU |
30.056 AU | |
Eccentricity | 0.0795 |
164.78 yr (60,186 days) | |
185.24° | |
0° 0m 21.6s / day | |
Inclination | 27.496° |
88.493° | |
6.7420° | |
Physical characteristics | |
Dimensions | |
23.2 [5] [6] | |
8.2 [1] | |
2008 LC18 is a Neptune trojan first observed on 7 June 2008 by American astronomers Scott Sheppard and Chad Trujillo using the Subaru Telescope at Mauna Kea Observatories on Hawaii, United States. [6] It was the first object found in Neptune's trailing L5 Lagrangian point and measures approximately 100 kilometers in diameter. [5]
Neptune trojans are resonant trans-Neptunian objects in a 1:1 mean-motion orbital resonance with Neptune. These trojans have a semi-major axis and an orbital period very similar to Neptune's (30.10 AU; 164.8 years).
2008 LC18 belongs to the trailing L5 group, which follow 60° behind Neptune's orbit. It orbits the Sun with a semi-major axis of 30.056 AU at a distance of 27.7–32.4 AU once every 164 years and 9 months (60,186 days). Its orbit has an eccentricity of 0.08 and an inclination of 27.4° with respect to the ecliptic. [1] This object has the second highest inclination of any known Neptune trojan after 2011 HM102 , which has 29.3°. [3]
The search for L5 trojans of Neptune has been impeded by the fact that this region of space is currently along the line of sight to the center of the Milky Way, an area of the sky crowded with stars. 2008 LC18 was found in a location where background stars are obscured by a dust cloud. [6] [5] The discovery of one Neptune L5 trojan in a searched area of 19 square degrees suggests that there may be 150 Neptune L5 trojans with a diameter greater than ~80 km (24th magnitude), similar to the estimate of such objects in Neptune's L4 swarm. [6]
2008 LC18 was not close enough for investigation by the New Horizons spacecraft when it crossed Neptune's L5 region en route to Pluto in 2013–2014, but its discovery showed that other, more accessible Neptune trojans could potentially have been found before that time. [7] 2008 LC18 was 2 AU from Pluto in 1997. [8] 2008 LC18 crossed the ecliptic plane in 2011. As of 2016 [update] , it is 33 AU from Neptune.
The discoverers estimate that the body has a mean-diameter of 100 kilometers based on a magnitude of 23.2. [5] [6] Based on a generic magnitude-to-diameter conversion, it measures approximately 98 kilometers in diameter using an absolute magnitude of 8.2 with an assumed albedo of 0.10. [4]
Due to its orbital uncertainty, this minor planet has not been numbered and its official discoverers have not been determined. [1] [2] If named, it will follow the naming scheme already established with 385571 Otrera, which is to name these objects after figures related to the Amazons, an all-female warrior tribe that fought in the Trojan War on the side of the Trojans against the Greek. [9]
(612243) 2001 QR322, prov. designation: 2001 QR322, is a minor planet and the first Neptune trojan discovered, by American astronomer Marc Buie of the Deep Ecliptic Survey at Cerro Tololo Observatory in Chile on 21 August 2001. It orbits ahead of Neptune at its L4 Lagrangian point and measures approximately 132 kilometers (82 miles) in diameter.
385571 Otrera, provisional designation 2004 UP10, is a Neptune trojan leading Neptune's orbit in the outer Solar System. It was discovered by American astronomers Scott Sheppard and Chad Trujillo at Las Campanas Observatory on 16 October 2004. It measures approximately 100 kilometers in diameter and was the second such body to be discovered after 2001 QR322.
Neptune trojans are bodies that orbit the Sun near one of the stable Lagrangian points of Neptune, similar to the trojans of other planets. They therefore have approximately the same orbital period as Neptune and follow roughly the same orbital path. Thirty-one Neptune trojans are currently known, of which 27 orbit near the Sun–Neptune L4 Lagrangian point 60° ahead of Neptune and four orbit near Neptune's L5 region 60° behind Neptune. The Neptune trojans are termed 'trojans' by analogy with the Jupiter trojans.
2005 TN53 is an inclined Neptune trojan leading Neptune's orbit in the outer Solar System, approximately 80 kilometers in diameter. It was first observed on 7 October 2005, by American astronomers Scott Sheppard and Chad Trujillo at Las Campanas Observatory in the Atacama desert of Chile. It was the third such body to be discovered, and the first with a significant orbital inclination, which showed that the population as a whole is very dynamically excited.
385695 Clete, provisional designation 2005 TO74, is a Neptune trojan, co-orbital with the ice giant Neptune, approximately 97 kilometers (60 miles) in diameter. It was named after Clete, one of the Amazons from Greek mythology. The minor planet was discovered on 8 October 2005, by American astronomers Scott Sheppard and Chad Trujillo at Las Campanas Observatory in Chile. 23 known Neptune trojans have already been discovered.
(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.
(118228) 1996 TQ66 (provisional designation 1996 TQ66) is a resonant trans-Neptunian object of the plutino population in the Kuiper belt, located in the outermost region of the Solar System. It was discovered on 8 October 1996, by American astronomers Jun Chen, David Jewitt, Chad Trujillo, and Jane Luu, using the UH88 telescope at the Mauna Kea Observatories, Hawaii. The very red object measures approximately 185 kilometers (110 miles) in diameter. As of 2021, it has not been named.
(613490) 2006 RJ103 is a Neptune trojan, first observed by the Sloan Digital Sky Survey Collaboration at Apache Point Observatory, New Mexico, on 12 September 2006. It was the fifth and largest such body discovered, approximately 180 kilometers in diameter. As of 2016, it is 30.3 AU from Neptune.
(527604) 2007 VL305, provisional designation 2007 VL305, is an inclined Neptune trojan that shares Neptune's orbit in the L4 Lagrangian point. It was discovered on 4 November 2007, by astronomers Andrew Becker, Andrew Puckett and Jeremy Kubica at the Apache Point Observatory in New Mexico, United States, although images from 2005 have also been recovered. It measures approximately 160 kilometers in diameter and was the sixth Neptune trojan to be discovered. As of 2016, it is 34.1 AU from Neptune.
(612584) 2003 QX113 is a large trans-Neptunian object from the scattered disc located in the outermost region of the Solar System. It is one of the most distant objects from the Sun at 60.5 AU. It was discovered by astronomers with the Canada–France Ecliptic Plane Survey at Mauna Kea Observatories, Hawaii, when it was near aphelion on 31 August 2003. It was provisionally designated 2003 QX113.
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.
2004 KV18 is an eccentric Neptune trojan trailing Neptune's orbit in the outer Solar System, approximately 70 kilometers in diameter. It was first observed on 24 May 2004, by astronomers at the Mauna Kea Observatories on Hawaii, United States. It was the eighth Neptune trojan identified and the second in Neptune's L5 Lagrangian point.
2011 HM102 is the ninth Neptune trojan discovered. It was first observed on 29 April 2011, during the New Horizons KBO Search (268) using the Magellan II (Clay) Telescope at Las Campanas Observatory in Chile. It has the same orbital period as Neptune and orbits at the L5 Lagrangian point about 60° backwards of Neptune.
(523671) 2013 FZ27 (provisional designation 2013 FZ27) is a trans-Neptunian object located in the Kuiper belt in the outermost region of the Solar System, approximately 570 kilometers (350 miles) in diameter. It was discovered on 16 March 2013, by American astronomers Scott Sheppard and Chad Trujillo at the CTIO in Chile. Numbered in 2018, this minor planet has not been named.
2014 FC69 is a trans-Neptunian object of the scattered disc on an eccentric orbit in the outermost region of the Solar System. It was first observed on 25 March 2014, by American astronomers Scott Sheppard and Chad Trujillo at the Cerro Tololo Observatory in Chile. It is one of the most distant objects from the Sun, even further away than Sedna.
(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.
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.
(678191) 2017 OF69 is a resonant trans-Neptunian object from the Kuiper belt, located in the outermost region of the Solar System in the Kuiper belt's plutino population and measures approximately 533 kilometers (330 miles) in diameter. It was first observed on 26 July 2017, by American astronomers David Tholen, Scott Sheppard, and Chad Trujillo at Mauna Kea Observatories in Hawaii, but not announced until 31 May 2018 due to observations made in April and May 2018 refining its orbit significantly.
(690420) 2014 FC72 is a trans-Neptunian object, classified as a scattered and detached object, located in the outermost region of the Solar System. It was first observed on 24 March 2014 by astronomers with the Pan-STARRS survey at Haleakala Observatory, Hawaii, United States. With its perihelion distant from Neptune, it belongs to a small and poorly understood group of objects with moderate eccentricities. It is estimated to measure 500 kilometers (300 miles) in diameter, assuming a low albedo.
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.