11351 Leucus

11351 Leucus (/ˈljuːkəs/), provisional designation 1997 TS₂₅, is a dark Jupiter trojan. It is an exceptionally slow rotator approximately 42 kilometers in diameter. It was discovered on 12 October 1997, by the Beijing Schmidt CCD Asteroid Program (SCAP) at Xinglong Station in the Chinese province of Hebei.

The C-type asteroid is located in the Greek camp of Jupiter's leading L₄ Lagrangian point. It orbits the Sun at a distance of 4.9–5.6 AU once every 12 years and 2 months (4,438 days). Its orbit has an eccentricity of 0.06 and an inclination of 12° with respect to the ecliptic. The first precovery was taken at Siding Spring Observatory in 1982, extending the asteroid's observation arc by 15 years prior to its discovery.

During spring 2013, a rotational light-curve was obtained from photometric observations made by Robert Stevens and Daniel Coley at the Center for Solar System Studies (CS3), California, using a 0.35/0.4-meter Schmidt-Cassegrain telescope. The light-curve showed an exceptionally slow rotation period of 7002515000000000000♠515±1.3 hours with a brightness variation of 6999530000000000000♠0.53±0.1 in magnitude (U=2+). No evidence of a non-principal axis rotation (NPAR) was found.

According to the surveys carried out by the Infrared Astronomical Satellite, IRAS, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the body has a low albedo of 0.06 and 0.08, with a diameter of 42.1 and 34.2 kilometers, respectively. The Collaborative Asteroid Lightcurve Link derives a lower albedo of 0.05 and a diameter of 42.1 kilometers, in accordance with the result obtained by IRAS.

The minor planet was named from Greek mythology, after the Achaean warrior Leucus in Homer's Iliad. He was a companion of Odysseus. Leucus was killed during the Trojan War by Antiphus, one of the fifty sons of King Priam of Troy. Naming citation was published on 22 February 2016 (M.P.C. 98711).