4341 Poseidon

4341 Poseidon, provisional designation 1987 KF, is a rare-type asteroid classified as near-Earth object of the Apollo group, approximately 2.3 kilometers in diameter. It was discovered by American astronomer Carolyn Shoemaker at Palomar Observatory on 29 May 1987.

The O-type asteroid orbits the Sun at a distance of 0.6–3.1 AU once every 2 years and 6 months (908 days). Its orbit has an eccentricity of 0.68 and an inclination of 12° with respect to the ecliptic. As no precoveries were taken, the asteroid's observation arc begins with its discovery in 1987. Poseidon may be associated with the Taurid Complex of meteor showers.

The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.18 and derives a diameter of 2.32 kilometers, based on an absolute magnitude of 15.65. In 1998, a rotational light-curve for this asteroid was published from photometric observations made by Czech astronomer Petr Pravec at Ondřejov Observatory. It gave a period of 7000626200000000000♠6.262 hours with a brightness variation of 0.08 magnitude (U=2). A second light-curve was obtained during the Near-Earth Objects Follow-up Program which gave a concurring period of 7000626560000000000♠6.2656 hours and an amplitude of 0.07 magnitude (U=2). A low brightness variation typically indicates that the body has a nearly spheroidal shape.

The minor planet was named for the "God of the Sea", Poseidon, one of the Twelve Olympians in Greek mythology. He was also referred to as "Earth-Shaker" due to his role in provoking earthquakes, which were then thought to be caused by ocean waves beating on the shore. He was the brother of Zeus (see 5731 Zeus), and an enemy of the Trojans in the Trojan War. Naming citation was published on 30 January 1991 (M.P.C. 17656).