Orbit of 2018 VG18 in the Solar System
|Discovered by||S. S. Sheppard|
|Discovery site||Mauna Kea Obs.|
|Discovery date||10 November 2018|
(first observed only)
|MPC designation||2018 VG18|
|centaur, TNO  · SDO |
ETNO · distant 
|Orbital characteristics |
|Epoch 25 November 2018 (JD 2458447.5)|
|Uncertainty parameter 9|
|Observation arc||32 days|
|0° 0m 3.96s / day|
|844 km (est.)|
500 km (est.)
2018 VG18 is the first trans-Neptunian object discovered while beyond 100 AU (15 billion km) from the Sun. The object was first observed on 10 November 2018 by astronomers Scott Sheppard, David Tholen, and Chad Trujillo during a search for the hypothetical Planet Nine, and they nicknamed it Farout to emphasize its distance from the Sun.
As of 2019[update] the object is at an observed distance of roughly 125 AU (19 billion km). This is more than three times the average distance of Pluto from the Sun, and nearly twice the average distance of Eris. 2018 VG18 was the most distant natural object ever observed in the Solar System, displacing the previous record holder, Eris, at 96 AU, until it was itself beaten by an object initially estimated at 140 AU (21 billion km) nicknamed "FarFarOut". However, 2018 VG18 is not close to being the object with the most distant orbit on average, as its semi-major axis is estimated to be only about 95 AU; in comparison, the semi-major axis of 2014 FE72 is 1550 AU.
Due to its orbital uncertainty, this object has not yet been assigned an official number. It should receive a number when there are observations at four or more oppositions. The International Astronomical Union's Minor Planet Center has assigned it the provisional designation 2018 VG18. The individuals involved in the object's discovery used the nickname Farout because the object was discovered so far from the Sun.
According to the Minor Planet Center, the current heliocentric distance of 2018 VG18 is 125 to 130 AU, but the specific details of the orbit such as the orbital eccentricity have not yet been established. JPL's Small-Body Database formally estimates it to be currently outbound 125±29 AU from the Sun.[note 1] It is receding from the Sun at a rate of ~1 AU every 3 years. As of February 2019[update] only data based on a short 32 day observation arc are published, and it may take several years of observation to properly characterize the orbit, due to the slow motion of the object.
There are two potential precovery observations, one from 2015 and one from 2017, but the orbital uncertainty needs to be reduced in order to definitively link the current observation arc of 2018 VG18 to these candidate observations.
Many near-parabolic comets are much further from the Sun. Caesar's Comet (C/-43 K1) is calculated to be more than 800 AU (120 billion km) from the Sun. Comet Donati (C/1858 L1) is 145 AU (22 billion km) from the Sun.
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