2018 VG18

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2018 VG18
2018VG18-SolarSystem-Orbit.png
Orbit of 2018 VG18 in the Solar System
Discovery [1][2]
Discovered byS. S. Sheppard
D. Tholen
C. Trujillo
Discovery siteMauna Kea Obs.
Discovery date10 November 2018
(first observed only)
Designations
MPC designation2018 VG18
"Farout" (nickname)[3][4]
TNO[5] · SDO[6]
ETNO · distant[2]
Orbital characteristics[5]
Epoch 25 November 2018 (JD 2458447.5)
Uncertainty parameter 9
Observation arc32 days
Aphelion168.7±4225.7 AU
Perihelion21.7±114.0 AU
95.2±2385 AU
Eccentricity0.772±4.925
929±34900 years
73.77°±4021.5°
0° 0m 3.96s / day
Inclination31.7°±145.6°
247.4°±32.6°
32.9°±1107.3°
Physical characteristics
Mean diameter
844 km (est.)[7]
500 km (est.)[3]
24.6
3.6±0.5[5]

2018 VG18 is the first trans-Neptunian object discovered while beyond 100 AU (15 billion km) from the Sun.[4] 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.[3]

As of 2019 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".[8] 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.

Physical characteristics[edit]

The diameter of 2018 VG18 is estimated to be about 500 km (310 mi), making it a possible dwarf planet.[3] It is pinkish in color.[9]

Nomenclature[edit]

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.[1][9] The individuals involved in the object's discovery used the nickname Farout because the object was discovered so far from the Sun.[9]

Orbit[edit]

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.[1] JPL's Small-Body Database formally estimates it to be currently outbound 125±29 AU from the Sun.[note 1][10] It is receding from the Sun at a rate of ~1 AU every 3 years. As of February 2019 only data based on a short 32 day observation arc are published,[5] and it may take several years of observation to properly characterize the orbit, due to the slow motion of the object.[11]

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.[12]

The orbit of 2018 VG18
Compared to the Solar System (from below the ecliptic)
Compared to Eris and other TNOs. (from above the ecliptic)
Retrograde motion in the sky through Taurus

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.[13] Comet Donati (C/1858 L1) is 145 AU (22 billion km) from the Sun.[14]

See also[edit]

Notes[edit]

  1. ^ This formal estimation of its distance from the Sun makes no assumptions about its orbit, simply fitting the observations to any possible orbit, including nearly-impossible ones such as orbits completely unbound to the Sun (Eccentricity>1), Oort-cloud object orbits, and orbits entering the inner solar system.

References[edit]

  1. ^ a b c "MPEC 2018-Y14 : 2018 VG18". Minor Planet Electronic Circular. 17 December 2018. Retrieved 29 December 2018.
  2. ^ a b "2018 VG18". Minor Planet Center. Retrieved 29 December 2018.
  3. ^ a b c d "Discovered: The Most-Distant Solar System Object Ever Observed". Carnegie Science. 17 December 2018. Retrieved 29 December 2018.
  4. ^ a b Chang, Kenneth (17 December 2018). "It's the Solar System's Most Distant Object. Astronomers Named It Farout". The New York Times. Retrieved 29 December 2018.
  5. ^ a b c d "JPL Small-Body Database Browser: (2018 VG18)" (2018-12-12 last obs.). Jet Propulsion Laboratory. Archived from the original on 22 February 2019. Retrieved 2 March 2019.
  6. ^ "List Of Centaurs and Scattered-Disk Objects". Minor Planet Center. Retrieved 29 December 2018.
  7. ^ Johnston, Wm. Robert (7 October 2018). "List of Known Trans-Neptunian Objects". Johnston's Archive. Retrieved 11 August 2019.
  8. ^ Paul Voosen (21 February 2019). "Astronomers discover solar system's most distant object, nicknamed 'FarFarOut'". Science magazine. Retrieved 26 February 2019.
  9. ^ a b c Strickland, Ashley (17 December 2018). "'Farout,' the most-distant solar system object discovered". CNN.com. Retrieved 29 December 2018.
  10. ^ "HORIZONS Web-Interface". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 22 December 2018.
  11. ^ "'Farout!' Newfound Object Is the Farthest Solar System Body Ever Spotted". Space.com. Retrieved 18 December 2018.
  12. ^ Dave Tholen (18 December 2018). "Re: {MPML} 2018 VG18". Retrieved 22 December 2018.
  13. ^ "Horizon Online Ephemeris System for -43K1". California Institute of Technology, Jet Propulsion Laboratory. Retrieved 16 November 2015.
  14. ^ JPL Horizons On-Line Ephemeris System. "JPL Horizons On-Line Ephemeris for Comet C/1858 L1 (Donati)". Retrieved 23 February 2019.
    Observer Location: @sun

External links[edit]