2018 VG18

Lore & Background

2018 VG18 was discovered as part of a search for TNOs whose orbits might be gravitationally influenced by the hypothetical Planet Nine. It was first identified in images taken with the 8.2-meter Subaru Telescope on 10 November 2018, appearing as a faint object of apparent magnitude 24.6 in the constellation Taurus. Follow-up observations were made in December 2018 at Las Campanas Observatory, and the discovery was announced on 17 December 2018.

The object has a highly elongated orbit with an eccentricity of about 0.53, varying from 38 AU at perihelion to 125 AU at aphelion, and is inclined 24 degrees to the ecliptic. It is in a 2:9 orbital resonance with Neptune and is classified as a scattered-disc object. As of 2024, it is 123.6 AU from the Sun and moving farther away, expected to reach aphelion in 2063. Its size is unmeasured but estimated to be in the range of 490 to 790 km in diameter if it has a moderate albedo.

Reader's Guide

2018 VG18 is significant as the first object discovered while beyond 100 astronomical units from the Sun, overtaking the dwarf planet Eris in observed distance. It was the farthest known TNO until February 2019, when 2018 AG37 ('FarFarOut') was discovered at about 132 AU. The object's discovery and subsequent observations have contributed to the search for the hypothetical Planet Nine, as its orbit may be gravitationally perturbed by such a planet. Its distance places it near the heliopause, the boundary where the solar wind meets interstellar space. The Hubble Space Telescope is planned to image 2018 VG18 in 2026 to determine if it has significantly sized moons. As of 2024, it remains the second-most distant observed natural object in the Solar System, and its orbit, while distant, is not the most distant in terms of average orbital distance, with objects like Sedna having much larger semi-major axes.

Did You Know?

• 2018 VG18 was nicknamed 'Farout' because it was the farthest known TNO at the time of its discovery.
• It was discovered by the same team that found 2012 VP113 and 541132 Leleākūhonua.
• As of 2024, 2018 VG18 is 123.6 AU from the Sun and is moving farther away until it reaches aphelion in 2063.