Key Facts

  • Categorized as a Aten-class Asteroid
  • Comparable in size to the Golden Gate Bridge (0.59 km diameter)
  • Will pass within 20,776,681 km of Earth in 2021
  • Classified as a Near Earth Asteroid (NEA)
  • Not a Potentially Hazardous Object
  • See orbit simulation

Overview

85953 (1999 FK21) is a small asteroid whose orbit could bring it in close proximity to Earth. NASA JPL has classified 1999 FK21 as a "Near Earth Asteroid" due to its orbit's proximity to Earth, but it is not considered potentially hazardous because computer simulations have not indicated any imminent likelihood of future collision.

1999 FK21 orbits the sun every 232 days (0.64 years), coming as close as 0.22 AU and reaching as far as 1.26 AU from the sun. Its orbit is highly elliptical. 1999 FK21 is about 0.6 kilometers in diameter, making it small in absolute terms, but larger than ~97% of asteroids, comparable in size to the Golden Gate Bridge.

The rotation of 1999 FK21 has been observed. It completes a rotation on its axis every 68.44 days.

1999 FK21's spectral type None (Tholen) / S (SMASSII) indicates that it is likely to contain magnesium silicate and iron silicate.

Close Approaches

1999 FK21's orbit is 0.07 AU from Earth's orbit at its closest point. This means that there is an wide berth between this asteroid and Earth at all times.

1999 FK21 has 44 close approaches predicted in the coming decades:

Date Distance from Earth (km) Velocity (km/s)
Feb. 16, 2021 20,776,681 21.609
April 8, 2025 12,078,443 18.988
Feb. 16, 2028 18,552,593 19.435
April 7, 2032 11,295,170 20.839
Feb. 17, 2035 21,523,181 17.805
April 7, 2039 18,721,971 23.252
Feb. 20, 2042 27,402,179 16.716
April 4, 2046 29,562,801 25.991
April 1, 2051 28,830,153 16.415
April 6, 2058 21,459,634 17.104
Feb. 16, 2061 22,590,980 22.387
April 8, 2065 14,081,048 18.438
Feb. 16, 2068 18,537,500 20.143
April 8, 2072 10,753,137 20.117
Feb. 17, 2075 19,876,872 18.352
April 8, 2079 15,503,674 22.331
Feb. 19, 2082 25,077,714 17.016
April 6, 2086 25,171,625 24.893
April 4, 2098 24,569,236 16.768
Feb. 18, 2101 25,648,175 23.451
April 8, 2105 17,076,245 17.820
Feb. 18, 2108 19,537,990 21.091
April 9, 2112 11,593,225 19.305
Feb. 17, 2115 18,573,371 19.063
April 10, 2119 12,657,760 21.355
Feb. 19, 2122 22,529,208 17.493
April 8, 2126 20,612,139 23.704
Feb. 22, 2129 28,073,971 16.634
April 4, 2138 27,649,624 16.505
Feb. 20, 2141 29,448,801 24.627
April 7, 2145 20,377,508 17.268
Feb. 19, 2148 21,609,745 22.107
April 9, 2152 13,631,002 18.604
Feb. 18, 2155 18,165,031 19.836
April 10, 2159 11,251,121 20.510
Feb. 18, 2162 20,488,246 18.042
April 9, 2166 17,059,861 22.721
Feb. 21, 2169 25,736,463 16.901
April 6, 2173 27,143,365 25.345
April 6, 2185 22,945,990 16.942
Feb. 19, 2188 23,756,663 22.907
April 9, 2192 15,590,618 18.148
Feb. 18, 2195 18,422,953 20.453
April 10, 2199 11,153,581 19.959

Images and Observations

1999 FK21's orbit is determined by observations dating back to March 26, 1971. It was last officially observed on Jan. 28, 2020. The IAU Minor Planet Center records 1,178 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 1999 FK21:

References

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Orbital Elements

  • Epoch: 2459000.5 JD
  • Semi-major axis: 0.7387 AU
  • Eccentricity: 0.7031
  • Inclination: 12.6°
  • Longitude of Ascending Node: 180.49°
  • Argument of Periapsis: 172.38°
  • Mean Anomaly: 34.75°

Physical Characteristics

  • Diameter: 0.59000 km
  • Magnitude: 18.1
  • Albedo: 0.32
  • Spectral type (SMASS): S

Derived Characteristics

  • Orbit Period: 232 days (0.64 years)
  • Avg. Orbit Speed: 34.64 km/s
  • Aphelion Distance: 1.26 AU
  • Perihelion Distance: 0.22 AU
  • Rotation Period: 68.44 hours
  • Approx. Composition: magnesium silicate and iron silicate.

Map Comparison

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Orbit Simulation

Sky Map

The position of 85953 (1999 FK21) 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.