1999 OJ4 orbit characterizes it as a classical Kuiper Belt object, or cubewano. Due to its nearly circular orbit and low inclination, it is also in the "cold" population of cubewanos. As a result, it is likely reddish in color.[10][11]
Satellite
1999 OJ4 has one moon, S/2005 (1999 OJ4) 1. This moon was discovered by the Hubble Space Telescope[9] on 5 October 2013. It orbits 3306±17 km away from 1999 OJ4, completing one orbit every 84.1147±0.0050 d. The orbit has an eccentricity of 0.3683±0.0038.[7]
At about 72 km, it is nearly the same size as 1999 OJ4. From the surface of 1999 OJ4, S/2005 (1999 OJ4) 1 would have an apparent diameter of roughly 8.11°,[a] over fourteen times the apparent size of the Sun from Earth.
^A. Doressoundiram; N. Peixinho; C. de Bergh; S. Fornasier; P. Thebault; M. A. Barucci; et al. (October 2002). "The Color Distribution in the Edgeworth-Kuiper Belt". The Astronomical Journal. 124 (4): 2279. arXiv:astro-ph/0206468. Bibcode:2002AJ....124.2279D. doi:10.1086/342447.