Key Facts
- Categorized as a Apollo-class Asteroid
- Comparable in size to the Golden Gate Bridge
- Will pass within 4,911,130 km of Earth in 2022
- Classified as a Near Earth Asteroid (NEA)
- Classified as a Potentially Hazardous Asteroid (PHA)
- See orbit simulation
Overview
138971 (2001 CB21) is a small asteroid whose orbit crosses the orbit of Earth. NASA JPL has classified 2001 CB21 as a "Potentially Hazardous Asteroid" due to its predicted close pass(es) with Earth.
2001 CB21 orbits the sun every 384 days (1.05 years), coming as close as 0.69 AU and reaching as far as 1.38 AU from the sun. Based on its brightness and the way it reflects light, 2001 CB21 is probably between 0.523 to 1.170 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 2001 CB21 has been observed. It completes a rotation on its axis every 3.30 hours.
Close Approaches
2001 CB21's orbit is 0.02 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.
2001 CB21 has 21 close approaches predicted in the coming decades:
| Date | Distance from Earth (km) | Velocity (km/s) |
|---|---|---|
| March 4, 2022 | 4,911,130 | 12.017 |
| Sept. 29, 2026 | 8,096,825 | 10.228 |
| March 6, 2043 | 4,815,332 | 10.779 |
| Oct. 1, 2047 | 5,384,739 | 11.329 |
| Feb. 26, 2063 | 25,969,363 | 16.375 |
| March 11, 2064 | 22,273,417 | 7.431 |
| Sept. 17, 2067 | 27,512,702 | 6.758 |
| Oct. 6, 2068 | 21,111,872 | 15.270 |
| March 3, 2084 | 6,502,640 | 12.440 |
| Sept. 27, 2088 | 11,955,385 | 9.412 |
| March 3, 2105 | 11,007,496 | 13.374 |
| Sept. 24, 2109 | 22,088,040 | 7.542 |
| Oct. 9, 2110 | 24,341,231 | 15.889 |
| March 9, 2127 | 10,661,261 | 9.501 |
| Oct. 2, 2131 | 5,685,865 | 11.404 |
| March 6, 2148 | 3,616,491 | 11.076 |
| Sept. 30, 2152 | 6,538,600 | 10.759 |
| March 7, 2169 | 4,242,865 | 10.838 |
| Oct. 2, 2173 | 5,727,857 | 11.423 |
| March 1, 2189 | 17,433,234 | 14.667 |
| Sept. 25, 2193 | 18,520,312 | 8.172 |
Images and Observations
2001 CB21's orbit is determined by observations dating back to Feb. 2, 2001. It was last officially observed on Dec. 23, 2022. The IAU Minor Planet Center records 1,803 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 2001 CB21:References
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or view a random objectOrbital Elements
- Epoch: 2460000.5 JD
- Semi-major axis: 1.034 AU
- Eccentricity: 0.3333
- Inclination: 7.92°
- Longitude of Ascending Node: 353.68°
- Argument of Periapsis: 271.94°
- Mean Anomaly: 273.14°
Physical Characteristics
- Diameter: ~0.675 km
- Magnitude: 18.53
Derived Characteristics
- Orbit Period: 384 days (1.05 years)
- Avg. Orbit Speed: 29.29 km/s
- Aphelion Distance: 1.38 AU
- Perihelion Distance: 0.69 AU
- Rotation Period: 3.30 hours
Map Comparison
Orbit Simulation
Sky Map
The position of 138971 (2001 CB21) 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 2001 CB21 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.
