Key Facts
- Categorized as a Apollo-class Asteroid
- Comparable in size to the Golden Gate Bridge
- Will pass within 12,597,362 km of Earth in 2032
- Classified as a Near Earth Asteroid (NEA)
- Classified as a Potentially Hazardous Asteroid (PHA)
- See orbit simulation
Overview
2009 HD21 is a small asteroid whose orbit crosses the orbit of Earth. NASA JPL has classified 2009 HD21 as a "Potentially Hazardous Asteroid" due to its predicted close pass(es) with Earth.
2009 HD21 orbits the sun every 1,680 days (4.60 years), coming as close as 0.86 AU and reaching as far as 4.68 AU from the sun. Based on its brightness and the way it reflects light, 2009 HD21 is probably between 0.595 to 1.331 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.
Close Approaches
2009 HD21's orbit is 0.01 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.
2009 HD21 has 4 close approaches predicted in the coming decades:
| Date | Distance from Earth (km) | Velocity (km/s) |
|---|---|---|
| Oct. 1, 2032 | 12,597,362 | 20.157 |
| Sept. 11, 2069 | 12,745,973 | 16.069 |
| Sept. 2, 2106 | 23,185,592 | 15.598 |
| Sept. 1, 2189 | 21,133,769 | 16.064 |
Images and Observations
2009 HD21's orbit is determined by observations dating back to March 24, 2009. It was last officially observed on May 15, 2023. The IAU Minor Planet Center records 166 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 2009 HD21:References
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or view a random objectOrbital Elements
- Epoch: 2460200.5 JD
- Semi-major axis: 2.771 AU
- Eccentricity: 0.688
- Inclination: 18.65°
- Longitude of Ascending Node: 179.21°
- Argument of Periapsis: 134.31°
- Mean Anomaly: 17.8°
Physical Characteristics
- Diameter: ~0.768 km
- Magnitude: 18.25
Derived Characteristics
- Orbit Period: 1,680 days (4.60 years)
- Avg. Orbit Speed: 17.94 km/s
- Aphelion Distance: 4.68 AU
- Perihelion Distance: 0.86 AU
Map Comparison
Orbit Simulation
Sky Map
The position of 2009 HD21 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 2009 HD21 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.
