It orbits the Sun at a distance of 4.6–5.9 AU once every 12 years and 1 month (4,410 days; semi-major axis of 5.26 AU). Its orbit has an eccentricity of 0.12 and an inclination of 3° with respect to the ecliptic.[3] The body's observation arc begins with a precovery taken at Crimea–Nauchnij in September 1985, just three weeks prior to its official discovery observation at Anderson Mesa.[1]
In August 2015, photometric observations by the Kepler space telescope rendered another two lightcurves (U=3-/2+).[7][8][10] The best-rated one showed a period of 29.82±0.24 hours and a brightness variation of 0.21 magnitude.[8] Most asteroids have a shorter rotation period between 2 and 20 hours (also see List of slow rotators).
Diameter and albedo
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Demophon measures 45.68 kilometers in diameter and its surface has an albedo of 0.077,[6] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 53.16 kilometers based on an absolute magnitude of 10.1.[7]
100+ largest Jupiter trojans
Largest Jupiter Trojans by survey(A) (mean-diameter in kilometers; YoD: Year of Discovery)
Note: missing data was completed with figures from the JPL SBDB (query) and from the LCDB (query form) for the WISE/NEOWISE and SIMPS catalogs, respectively. These figures are given in italics. Also, listing is incomplete above #100.