Key Facts
- Categorized as a Amor-class Asteroid
- Comparable in size to the Golden Gate Bridge
- Will pass within 13,465,928 km of Earth in 2086
- Classified as a Near Earth Asteroid (NEA)
- Classified as a Potentially Hazardous Asteroid (PHA)
- See orbit simulation
Overview
6491 (1991 OA) is a small asteroid whose orbit approaches the orbit of Earth but does not cross it. NASA JPL has classified 1991 OA as a "Potentially Hazardous Asteroid" due to its predicted close pass(es) with Earth.
1991 OA orbits the sun every 1,450 days (3.97 years), coming as close as 1.02 AU and reaching as far as 3.98 AU from the sun. Based on its brightness and the way it reflects light, 1991 OA is probably between 0.475 to 1.062 kilometers in diameter, making it larger than ~97% of asteroids but small compared to large asteroids, very roughly comparable in size to the Golden Gate Bridge.
The rotation of 1991 OA has been observed. It completes a rotation on its axis every 2.69 hours.
Close Approaches
1991 OA's orbit is 0.04 AU from Earth's orbit at its closest point. This means that there is a wide berth between this asteroid and Earth at all times.
1991 OA has 5 close approaches predicted in the coming decades:
| Date | Distance from Earth (km) | Velocity (km/s) |
|---|---|---|
| Aug. 1, 2086 | 13,465,928 | 12.838 |
| Aug. 14, 2121 | 17,482,396 | 15.352 |
| Aug. 21, 2144 | 25,316,065 | 17.387 |
| June 24, 2167 | 17,352,014 | 11.422 |
| May 25, 2190 | 16,204,474 | 11.716 |
Images and Observations
1991 OA's orbit is determined by observations dating back to March 18, 1991. It was last officially observed on Oct. 8, 2019. The IAU Minor Planet Center records 190 observations used to determine its orbit.
Accessibility and Exploration
This asteroid is not considered a viable target for human exploration by the NHATS study.Similar Objects
These objects have orbits that share similar characteristics to the orbit of 1991 OA:References
Search
or view a random objectOrbital Elements
- Epoch: 2460200.5 JD
- Semi-major axis: 2.502 AU
- Eccentricity: 0.5904
- Inclination: 5.94°
- Longitude of Ascending Node: 301.88°
- Argument of Periapsis: 323.67°
- Mean Anomaly: 43.34°
Physical Characteristics
- Diameter: ~0.613 km
- Magnitude: 18.74
Derived Characteristics
- Orbit Period: 1,450 days (3.97 years)
- Avg. Orbit Speed: 18.77 km/s
- Aphelion Distance: 3.98 AU
- Perihelion Distance: 1.02 AU
- Rotation Period: 2.69 hours
Map Comparison
Orbit Simulation
Sky Map
The position of 6491 (1991 OA) is indicated by a ◯ pink circle. Note that the object may not be in your current field of view. Use the controls below to adjust position, location, and time.
Size Rendering
The above comparison is an artistic rendering that uses available data on the diameter of 1991 OA to create an approximate landscape rendering with Mount Everest in the background. This approximation is built for full-resolution desktop browsers. Shape, color, and texture of asteroid are imagined.
