2018 EC4

 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 10 March 2018 by the Mt. Lemmon Survey, but it had already been imaged (but not identified as an asteroid) by the Pan-STARRS 1 telescope system at Haleakala on 29 October 2011. Its orbit is characterized by low eccentricity (0.061), moderate inclination (21.8°) 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 70 observations with a data-arc span of 3,131 days. has an absolute magnitude of 20.1 which gives a characteristic diameter of 300 m.

Mars trojan and orbital evolution
Recent calculations indicate that it is a stable Mars trojan with a libration period of 1250 yr and an amplitude of 17°. These values are similar to those of 5261 Eureka and related objects and it may be a member of the so-called Eureka family.

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