2002 RN₁₀₉ is a trans-Neptunian astronomical object and damocloid on a highly eccentric, cometary-like orbit. It was first observed on 6 September 2002, by astronomers of the Lincoln Near-Earth Asteroid Research project at its ETS near Socorro, New Mexico, United States.^[1] The unusual object is approximately 4 kilometers (2 miles) in diameter.^[3] It has the second-highest orbital eccentricity of any known minor planet, after 2005 VX3.^[5]

Description

2002 RN₁₀₉ 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. It orbits the Sun at a distance of 2.7–1,091 AU once every 12,783 years (semi-major axis of 546.7 AU). Its orbit has an eccentricity of 0.9951 and an inclination of 58° with respect to the ecliptic.^[2] The body's observation arc began with a precovery observation at Lincoln Laboratory's Experimental Test Site on 16 August 2002, or three weeks prior to its first observation.^[1] The observation arc is only 80 days long. The object has not been observed since November 2002, about 2 months before it came to perihelion 2.7 AU from the Sun.^[2] During perihelion passage the object was 2.9 AU from Earth.

2002 RN₁₀₉ belongs to the dynamical group of damocloids due to its low Tisserand parameter (T_Jupiter of 1.0820).^[2] It is also a Jupiter-, Saturn-, Uranus-, and Neptune-crosser. The object has the seventh-largest heliocentric semi-major axis and aphelion of all known minor planets, while its extreme eccentricity brings it well within the orbit of Jupiter when at perihelion.