| Discovery[1] | |
|---|---|
| Discovered by | H. E. Holt |
| Discovery site | Palomar Obs. |
| Discovery date | 16 July 1991 |
| Designations | |
| (6491) 1991 OA | |
| NEO · Amor · PHA[1] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 24.35 yr (8,895 days) |
| Aphelion | 3.9772AU |
| Perihelion | 1.0227 AU |
| 2.5000 AU | |
| Eccentricity | 0.5909 |
| 3.95yr (1,444 days) | |
| 215.03° | |
| 0° 14m 57.48s / day | |
| Inclination | 5.9464° |
| 301.90° | |
| 323.60° | |
| Earth MOID | 0.0420 AU · 16.4LD |
| Physical characteristics | |
| Dimensions | 0.52 km(derived)[2] |
| 2.69h[3] | |
| 0.20(assumed)[2] | |
| S[2] | |
| 18.77[2][3] · 18.9[1] | |
(6491) 1991 OA is a highly eccentric, stonyasteroid, classified asnear-Earth object andpotentially hazardous asteroid, approximately half a kilometer in diameter. It was discovered on 16 July 1991, by American astronomerHenry E. Holt at the U.S.Palomar Observatory in California.[4]
TheS-type body is anAmor 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 aneccentricity of 0.59 and aninclination of 6° with respect to theecliptic.[1] Itsminimum orbit intersection distance (MOID) with Earth is 0.0420 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).[5]
A firstprecovery was taken at the AustralianSiding Spring Observatory in March 1991, extending the asteroid'sobservation arc by 4 months prior to its discovery.[4]
In 2000, a rotationallightcurve was published from photometric observations obtained by theNear-Earth Objects Follow-up Program during the early 1990s. The lightcurve rendered arotation period of 2.69 hours with an brightness amplitude of 0.08 inmagnitude (U=2).[3] TheCollaborative Asteroid Lightcurve Link (CALL) assumes analbedo of 0.20 and derives a diameter of 0.53 kilometers, based on anabsolute magnitude of 18.77.[2]
As of 2017,1991 OA remains unnamed.[4]
2011-09-29 last obs
