2016 CP31

 is a small asteroid and Mars trojan orbiting near the of Mars (60 degrees behind Mars on its orbit).

Discovery, orbit and physical properties
was first observed on 7 February 2016 by the Catalina Sky Survey; the Pan-STARRS 1 telescope system at Haleakala had imaged this object on 14 January 2016 without identifying it as an asteroid. Its orbit is characterized by low eccentricity (0.059), moderate inclination (23.1°) and a semi-major axis of 1.52 AU. Upon discovery, it was classified as Mars-crosser by the Minor Planet Center. Its orbit is well determined as it is currently (January 2021) based on 131 observations with a data-arc span of 1652 days. has an absolute magnitude of 19.5 which gives a characteristic diameter of 400 m.

Mars trojan and orbital evolution
Recent calculations indicate that it is a stable Mars trojan. It may not be a member of the so-called Eureka family.

Mars trojan
 (leading):  (trailing):
 * 5261 Eureka (1990 MB) †