2018 EC4 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.[3] Its orbit is characterized by low eccentricity (0.061), moderate inclination (21.8°) and a semi-major axis of 1.52 AU.[3] 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.[1]2018 EC4 has an absolute magnitude of 20.1 which gives a characteristic diameter of 300 m.[1]
Mars trojan and orbital evolution
Recent calculations indicate that it is a stable L5Mars trojan with a libration period of 1250 yr and an amplitude of 17°.[2] These values are similar to those of 5261 Eureka and related objects and it may be a member of the so-called Eureka family.[citation needed]
Three new stable L5 Mars Trojans de la Fuente Marcos, C., de la Fuente Marcos, R. 2013, Monthly Notices of the Royal Astronomical Society: Letters, Vol. 432, Issue 1, pp. 31–35.
