2018 VG 18

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Asteroid
2018 VG 18
Properties of the orbit ( animation )
Epoch:  May 31, 2020 ( JD 2,459,000.5)
Orbit type DO? or
SDO / Centaur , "Distant Object"
Major semi-axis 81.418  AU
eccentricity 0.536
Perihelion - aphelion 37.794 AU - 125.042 AU
Inclination of the orbit plane 24.4 °
Length of the ascending node 245.4 °
Argument of the periapsis 17.2 °
Time of passage of the perihelion April 12, 1700
Sidereal period 735 a
Mean orbital velocity 0.33 km / s
Physical Properties
Medium diameter approx. 500 km
Absolute brightness 3.5 likes
history
Explorer Scott S. Sheppard ,
David J. Tholen ,
Chadwick A. Trujillo
Date of discovery November 10, 2018
Another name "Farout"
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items.

2018 VG 18 is a large trans-Neptunian object that is classified as a scattered disc object , centaur or more generally as a "distant object" in terms of its orbit dynamics . Its distance from the Sun was around 120 AU at the time of discovery , making it the first object of its kind to be discovered at a distance of over 100 AU. Because of its size, the asteroid is a dwarf planet candidate .

discovery

2018 VG 18 was discovered on November 10, 2018 by an American team of astronomers consisting of Scott Sheppard , David Tholen and Chad Trujillo with the 8.2 m Subaru telescope at the Mauna Kea Observatory ( Hawaii ). The find resulted from a search for the previously postulated hypothetical planet nine . The discovery was announced on December 17, 2018.

The discoverers gave the object the nickname Farout (English "far out"; analogously also "crazy", "weird", but also "great", "great").

The asteroid's observation arc begins with the official discovery observation in November 2018. It was observed again in November 2019. So far, a total of 26 observations have been made over a period of 431 days. The last observation so far was on January 16, 2020 - at the La Palma observatory - carried out. There are currently two potential pre-discovery observations from 2015 and 2017, but the uncertainty values ​​of the orbit calculations must first be further reduced in order to be able to definitively link the current observation sheet with these candidate observations. Due to the slow movement of objects so far away, it takes several years to determine the orbit with high precision, but the uncertainty parameter is currently only less than 86.5 arc seconds per decade, so that larger corrections of the orbital elements are no longer to be expected (status April 14, 2020).

properties

The orbit of 2018 VG 18 (white) compared to other distant planetoids

Orbit

According to the current state of knowledge, 2018 VG 18 will move in approx. 735 years on a highly eccentric orbit with a distance to the sun between 37.8  AU and 125 AU. The eccentricity of the orbit ellipse is 0.72, the orbit plane is inclined 24.4 ° with respect to the ecliptic . The planetoid is currently about 120 AU from the sun and moving away from it at a speed of about 1.8 km / sec. It currently has an apparent magnitude of 24.3 mag - 25.7 mag. These fluctuations are an indication of differently bright surface structures and a rotation. He passed his perihelion for the last time in 1700, so the next perihelion would have to occur in 2435. In 2067 it will reach aphelion, which is the greatest distance from the sun. It will then have an apparent brightness of approx. 26.5 mag, ie it will definitely still be observable with large telescopes.

125 AU is more than three times the average distance from Pluto to the Sun and approximately twice the distance from Eris . At the time of discovery, 2018 VG 18 was the most distant of all objects in the solar system discovered so far and replaced the previous “record holder” Eris (96 AU). However, it is not the object with the furthest known orbit, as its major semi-axis is "only" about 81 AU, while the semi-axis of 2017 MB7 has around 3000 AU.

In 2018, the Minor Planet Center listed VG 18 as SDO / Centaur and generally as a “Distant Object”, while Marc Buie ( DES ) does not yet have a specific classification.

size

On the basis of brightness measurements it can be assumed that the diameter of the object is in the order of 500 kilometers. The object also has a pink hue on the surface. This color is associated with ice-rich objects.

Since it can be assumed that 2018 VG 18 will be in hydrostatic equilibrium due to its size and must therefore be largely round, it should meet the criteria for classification as a dwarf planet .

Many other objects that have already been discovered have orbital data with an aphelion of well over 100 AU, the most famous of which is Sedna with an aphelion of around 900 AU. However, Sedna is currently at around 85 AU near perihelion . This also applies to all other objects discovered so far with such eccentric orbit data, which means that they are currently significantly closer to the sun than 2018 VG 18 .

See also

Web links

Commons : 2018 VG18  - Collection of Images, Videos and Audio Files

Individual evidence

  1. a b MPC : List Of Centaurs and Scattered-Disk Objects . IAU . Retrieved February 5, 2019.
  2. a b c 2018 VG18 at the IAU Minor Planet Center (English)
  3. a b Discovered: The Most-Distant Solar System Object Ever Observed . Carnegie Science.
  4. Deborah Byrd: Astronomers spy most distant solar system object yet . Earthsky News.
  5. MPC : MPEC 2018-Y14: 2018 VG18 . IAU . December 17, 2018. Retrieved February 5, 2019.
  6. PONS: Far-out . PONS .
  7. 2018 VG18 in the Small-Body Database of the Jet Propulsion Laboratory (English). Retrieved February 5, 2019. Template: JPL Small-Body Database Browser / Maintenance / Alt