2011 SL25

, also written as 2011 SL25, is an asteroid and Mars trojan candidate that shares the orbit of the planet Mars at its point.

Discovery, orbit and physical properties
was discovered on 21 September 2011 at the Alianza S4 Observatory on Cerro Burek in Argentina and classified as Mars-crosser by the Minor Planet Center. It follows a relatively eccentric orbit (0.11) with a semi-major axis of 1.52 AU. This object has noticeable orbital inclination (21.5°). Its orbit was initially poorly constrained, with only 76 observations over 42 days, but was recovered in January 2014. has an absolute magnitude of 19.5 which gives a characteristic diameter of 575 m.

Mars trojan and orbital evolution
Recent calculations indicate that it is a stable Mars Trojan with a libration period of 1400 yr and an amplitude of 18°. values as well as its short-term orbital evolution are similar to those of 5261 Eureka.

Origin
Long-term numerical integrations show that its orbit is stable on Gyr time-scales (1 Gyr = 1 billion years). It appears to be stable at least for 4.5 Gyr but its current orbit indicates that it has not been a dynamical companion to Mars for the entire history of the Solar System.