| 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 | 3.9772 AU |
| Perihelion | 1.0227 AU |
| 2.5000 AU | |
| Eccentricity | 0.5909 |
| 3.95 yr (1,444 days) | |
| 215.03° | |
| 0° 14m 57.48s / day | |
| Inclination | 5.9464° |
| 301.90° | |
| 323.60° | |
| Earth MOID | 0.0420 AU · 16.4 LD |
| Physical characteristics | |
| Dimensions | 0.52 km (derived)[2] |
| 2.69 h[3] | |
| 0.20 (assumed)[2] | |
| S[2] | |
| 18.77[2][3] · 18.9[1] | |
(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.[4]
Orbit and classification
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.[1] Its minimum 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 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.[4]
Physical characteristics
In 2000, a rotational lightcurve was published from photometric observations obtained by the Near-Earth Objects Follow-up Program during the early 1990s. The lightcurve rendered a rotation period of 2.69 hours with an brightness amplitude of 0.08 in magnitude (U=2).[3] 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.[2]
Naming
As of 2017, 1991 OA remains unnamed.[4]
References
- 1 2 3 4 5 "JPL Small-Body Database Browser: 6491 (1991 OA)" (2015-07-25 last obs.). Jet Propulsion Laboratory. Retrieved 26 May 2017.
- 1 2 3 4 5 "LCDB Data for (6491)". Asteroid Lightcurve Database (LCDB). Retrieved 24 July 2016.
- 1 2 3 Erikson, A.; Mottola, S.; Lagerros, J. S. V.; Lindgren, M.; Piironen, J.; Oja, T.; et al. (October 2000). "The Near-Earth Objects Follow-up Program. III. 32 Lightcurves for 12 Objects from 1992 and 1995". Icarus. 147 (2): 487–497. Bibcode:2000Icar..147..487E. doi:10.1006/icar.2000.6457. Retrieved 1 January 2016.
- 1 2 3 "6491 (1991 OA)". Minor Planet Center. Retrieved 24 July 2016.
- ↑ "JPL Close-Approach Data: 6491 (1991 OA)". Retrieved 24 March 2012.
2011-09-29 last obs
External links
- Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
- Dictionary of Minor Planet Names, Google books
- Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
- (6491) 1991 OA at NeoDyS-2, Near Earth Objects—Dynamic Site
- (6491) 1991 OA at ESA–space situational awareness
- (6491) 1991 OA at the JPL Small-Body Database