Toutatis (Asteroid)

4179 Toutatis (provisional designation 1989 AC) is an elongated, stony asteroid and slow rotator, classified as a near-Earth object and potentially hazardous asteroid of the Apollo asteroid group, approximately 2.5 kilometers in diameter. Discovered by French astronomer Christian Pollas at Caussols in 1989, the asteroid was named after Toutatis from Celtic mythology. Toutatis is also a Mars-crosser asteroid with a chaotic orbit produced by a 3:1 resonance with the planet Jupiter, a 1:4 resonance with the planet Earth, and frequent close approaches to the terrestrial planets, including Earth. In December 2012, Toutatis passed within about 18 lunar distances of Earth. The Chinese lunar probe Chang'e 2 flew by the asteroid at a distance of 3.2 kilometers and a relative velocity of 10.73 km/s. Toutatis approached Earth again in 2016, but will not make another notably close approach until 2069.