1999 CD158 is a candidate member of the Haumea family, the only collisional group of trans-Neptunian objects currently determined.[6] It is also sub-classified as a resonant trans-Neptunian object, as it stays in a 4:7 orbital resonance with the ice giant Neptune, which means, that for every seven orbits of Neptune around the Sun, it makes four orbits. It orbits the Sun at a distance of 37.4–50.1 AU once every 289 years and 8 months (105,787 days). Its orbit has an eccentricity of 0.15 and an inclination of 25° with respect to the ecliptic.[1]
Its observation arc begins with its official discovery observation at Mauna Kea in 1999, as no precovery images were taken and no prior identifications were made.[3] As of 2017 its current position is at 46.7 AU from the Sun.[14]
Physical characteristics
Photometry
Photometric observation of 1999 CD158 in March 2015, gave a classically shaped bimodal lightcurve with a rotation period of 6.88 hours and a large brightness variation of 0.49 magnitude (U=3-).[6]
According to estimates by the Johnston's archive, the Collaborative Asteroid Lightcurve Link, and American astronomer Michael Brown, 1999 CD158 measures between 420 and 477 kilometers in diameter.[8][2][15] It is "probably" a dwarf planet" according to Brown's assessment (see List of possible dwarf planets § list).[15]