2005 VX3

2005 VX₃ is a trans-Neptunian object and retrograde damocloid on a highly eccentric, cometary-like orbit. It was first observed on 1 November 2005, by astronomers with the Mount Lemmon Survey at the Mount Lemmon Observatory in Arizona, United States. The unusual object measures approximately 7 kilometers (4 miles) in diameter.⁴ It has the 3rd largest known heliocentric semi-major axis and aphelion.⁶ Additionally its perihelion lies within the orbit of Jupiter, which means it also has the largest orbital eccentricity of any known minor planet.

2005 VX₃ orbits the Sun at a distance of 4.1–2,124 AU once every 34,717 years (semi-major axis of 1,064 AU). Its orbit has an eccentricity of 0.9961 and an inclination of 113° with respect to the ecliptic. It belongs to the dynamical group of damocloids due to its retrograde orbit and its low Tisserand parameter (T_Jupiter of −0.968).³ It is a Jupiter-, Saturn-, Uranus-, and Neptune-crosser. The body's observation arc begins with its first observation by the Mount Lemmon Survey on 1 November 2005.¹

2005 VX₃ has a barycentric semi-major axis of ~1026 AU.^7a 2014 FE72 and (668643) 2012 DR30 have a larger barycentric semi-major axis. The epoch of January 2016 was when 2005 VX₃ had its largest heliocentric semi-major axis.

The object has a short observation arc of 81 days and does not have a well constrained orbit.³ It has not been observed since January 2006, when it came to perihelion, 4.1 AU from the Sun.³ It may be a dormant comet that has not been seen outgassing. In the past it may have made closer approaches to the Sun that could have removed most near-surface volatiles. The current orbit crosses the ecliptic just inside Jupiter's orbit and has a Jupiter-MOID of 0.8 AU.³

In 2017, it had an apparent magnitude of ~28 and was 24 AU from the Sun. It comes to opposition in mid-June. It would require one of the largest telescopes in the world for any more follow-up observations.