Small asteroid and Mars trojan
2009 SE is a small asteroid and Mars trojan orbiting near the L5 point of Mars (60 degrees behind Mars on its orbit).
Discovery, orbit and physical properties.
2009 SE was first observed on 16 September 2009 by the Catalina Sky Survey (CSS). Its orbit is characterized by low eccentricity (0.065), moderate inclination (20.6°) 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 56 observations with a data-arc span of 3,133 days. 2009 SE has an absolute magnitude of 19.9 which gives a characteristic diameter of 400 m.
Mars trojan and orbital evolution.
Recent calculations indicate that it is a stable L5 Mars trojan with a libration period of 1430 yr and an amplitude of 70°. The libration amplitude is not similar to that of 5261 Eureka and related objects.
Mars trojan.
L4 ("leading"):
L5 ("trailing"):
References.
 ;templatestyles src="Reflist/styles.css" / ;