2021 CW4

Very small Apollo-class Asteroid

Near-Earth Potentially Hazardous
Space Reference » Apollo-class Asteroids » 2021 CW4

Key Facts

  • Categorized as a Apollo-class Asteroid
  • Comparable in size to the U.S. Capitol building
  • Will pass within 27,076,935 km of Earth in 2021
  • Classified as a Near Earth Asteroid (NEA)
  • Classified as a Potentially Hazardous Asteroid (PHA)
  • See orbit simulation

Overview

2021 CW4 is a very small asteroid whose orbit crosses the orbit of Earth. NASA JPL has classified 2021 CW4 as a "Potentially Hazardous Asteroid" due to its predicted close pass(es) with Earth.

2021 CW4 orbits the sun every 850 days (2.33 years), coming as close as 0.81 AU and reaching as far as 2.71 AU from the sun. Based on its brightness and the way it reflects light, 2021 CW4 is probably between 0.312 to 0.698 kilometers in diameter, making it larger than 90% of asteroids but tiny compared to large asteroids, very roughly comparable in size to the U.S. Capitol building.

Close Approaches

2021 CW4'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.

2021 CW4 has 26 close approaches predicted in the coming decades:

Date Distance from Earth (km) Velocity (km/s)
Feb. 10, 2021 27,076,935 17.210
Feb. 5, 2028 18,370,538 14.297
Jan. 29, 2035 17,504,570 12.151
Jan. 17, 2042 21,735,623 10.462
Jan. 2, 2049 26,051,460 10.359
Dec. 18, 2055 28,579,874 10.956
Dec. 3, 2062 29,002,785 11.293
Nov. 21, 2069 27,794,394 11.250
Nov. 6, 2076 24,311,309 10.896
Oct. 24, 2083 19,411,065 10.744
Oct. 14, 2090 13,980,931 11.198
Oct. 9, 2097 10,208,275 11.744
Oct. 9, 2104 9,095,770 11.972
Oct. 11, 2111 10,474,584 11.696
Oct. 16, 2118 14,028,768 11.168
Oct. 24, 2125 18,971,924 10.772
Nov. 3, 2132 23,213,812 10.814
Nov. 16, 2139 26,553,425 11.102
Nov. 28, 2146 28,639,028 11.315
Dec. 11, 2153 29,171,505 11.201
Dec. 25, 2160 28,026,033 10.754
Jan. 11, 2168 24,407,290 10.205
Jan. 24, 2175 19,639,481 10.907
Feb. 1, 2182 16,897,085 12.409
Feb. 7, 2189 18,343,219 14.488
Feb. 13, 2196 26,137,566 17.065

Images and Observations

2021 CW4's orbit is determined by observations dating back to Feb. 21, 2014. It was last officially observed on April 15, 2021. The IAU Minor Planet Center records 243 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 2021 CW4:

References

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Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 1.757 AU
  • Eccentricity: 0.5402
  • Inclination: 6.94°
  • Longitude of Ascending Node: 204.81°
  • Argument of Periapsis: 225.03°
  • Mean Anomaly: 58.55°

Physical Characteristics

  • Diameter: ~0.403 km
  • Magnitude: 19.65

Derived Characteristics

  • Orbit Period: 850 days (2.33 years)
  • Avg. Orbit Speed: 22.49 km/s
  • Aphelion Distance: 2.71 AU
  • Perihelion Distance: 0.81 AU

Map Comparison

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Orbit Simulation

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Sky Map

The position of 2021 CW4 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 below comparison is an artistic rendering that uses available data on the diameter of 2021 CW4 to create an approximate landscape rendering with New York City in the background. This approximation is built for full-resolution desktop browsers. Shape, color, and texture of asteroid are imagined.