9000 Hal, provisional designation 1981 JO, is a stony background asteroid and slow rotator from the inner regions of the asteroid belt, approximately 4 kilometers (2.5 miles) in diameter. It was discovered on 3 May 1981, by American astronomer Edward Bowell at Lowell's Anderson Mesa Station near Flagstaff, Arizona, in the United States.^[1] The likely elongated S-type asteroid has an exceptionally long rotation period of 908 hours.^[4] It was named after the homicidal supercomputer HAL 9000, featured in the 1968 film 2001: A Space Odyssey.^[1]

Hal is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.^[3] Based on osculating Keplerian orbital elements, the asteroid has also been classified as a member of the Flora family (402), a giant asteroid family and the largest family of stony asteroids in the main-belt.^[4]

Hal orbits the Sun in the inner asteroid belt at a distance of 1.8–2.7 AU once every 3 years and 4 months (1,216 days; semi-major axis of 2.23 AU). Its orbit has an eccentricity of 0.21 and an inclination of 6° with respect to the ecliptic.^[2] The asteroid was first observed as 1975 VH₃ at Crimea–Nauchnij in November 1975. The body's observation arc begins with its official discovery observation at Anderson Mesa in May 1981.^[1]

Hal is an assumed stony S-type asteroid, based on the Collaborative Asteroid Lightcurve Link's (CALL) classification into the Flora family.^[4]

This minor planet was named after the fictional supercomputer Hal 9000, featured in both Arthur C. Clarke's novel and Stanley Kubrick's movie 2001: A Space Odyssey (1968).^[1] HAL stands for Heuristically programmed Algorithmic computer. It is one of the best-known artificial intelligence characters in modern movies. The official naming citation was published by the Minor Planet Center on 4 May 1999 (M.P.C. 34628).^[11] The asteroid 4923 Clarke and 10221 Kubrick were named after the writer and movie director, respectively.