Samiksha Jaiswal (Editor)

(6491) 1991 OA

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Discovered by  H. E. Holt
MPC designation  (6491) 1991 OA
Observation arc  24.35 yr (8,895 days)
Discovered  16 July 1991
Orbits  Sun
Discovery site  Palomar Observatory
Discovery date  16 July 1991
Minor planet category  NEO · Amor · PHA
Perihelion  1.0233 AU
Aphelion  3.98 m
Discoverer  Henry E. Holt
Asteroid group  Amor asteroid
Similar  Sun, 6489 Golevka, 4179 Toutatis

(6491) 1991 OA is a highly eccentric, stony asteroid, classified as near-Earth object and potentially hazardous asteroid, approximately half a kilometer in diameter. It was discovered on 16 July 1991, by American astronomer Henry E. Holt at the U.S. Palomar Observatory in California.

The S-type body is an Amor asteroid – a subgroup of near-Earth asteroids that approach the orbit of Earth from beyond, but do not cross it. It orbits the Sun at a distance of 1.0–4.0 AU once every 3 years and 11 months (1,444 days). Its orbit has an eccentricity of 0.59 and an inclination of 6° with respect to the ecliptic. Its minimum orbit intersection distance (MOID) with Earth is 0.0429 AU, and on 1 August 2086, it will make a close approach and pass by Earth at a distance of 0.09 AU (13,000,000 km). The first precovery was taken at the Australian Siding Spring Observatory in March 1991, extending the asteroid's observation arc by 4 months prior to its discovery.

In 2000, a rotational light-curve was published from photometric observations obtained by the Near-Earth Objects Follow-up Program during the early 1990s. The light-curve rendered a rotation period of 2.69 hours with an brightness amplitude of 0.08 in magnitude (U=2). The Collaborative Asteroid Lightcurve Link (CALL) assumes an albedo of 0.20 and derives a diameter of 0.53 kilometers, based on an absolute magnitude of 18.77.


(6491) 1991 OA Wikipedia