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 very 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 (0.63 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 a small to average asteroid, 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 (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 12,078,431 18.988
Feb. 16, 2028 18,552,596 19.435
April 7, 2032 11,295,181 20.839
Feb. 17, 2035 21,523,204 17.805
April 7, 2039 18,722,031 23.252
Feb. 20, 2042 27,402,222 16.716
April 4, 2046 29,562,907 25.991
April 1, 2051 28,830,074 16.415
April 6, 2058 21,459,512 17.104
Feb. 16, 2061 22,590,867 22.387
April 8, 2065 14,080,913 18.438
Feb. 16, 2068 18,537,472 20.143
April 8, 2072 10,753,140 20.117
Feb. 17, 2075 19,876,985 18.352
April 8, 2079 15,503,955 22.331
Feb. 19, 2082 25,077,935 17.016
April 6, 2086 25,172,088 24.893
April 4, 2098 24,568,823 16.768
Feb. 18, 2101 25,647,681 23.451
April 8, 2105 17,075,759 17.820
Feb. 18, 2108 19,537,719 21.091
April 9, 2112 11,592,956 19.305
Feb. 17, 2115 18,573,523 19.062
April 10, 2119 12,658,253 21.356
Feb. 19, 2122 22,529,720 17.493
April 8, 2126 20,613,181 23.704
Feb. 22, 2129 28,074,623 16.634
April 4, 2138 27,648,769 16.505
Feb. 20, 2141 29,447,545 24.627
April 7, 2145 20,376,428 17.268
Feb. 19, 2148 21,608,824 22.106
April 9, 2152 13,630,082 18.604
Feb. 18, 2155 18,164,963 19.835
April 10, 2159 11,251,486 20.510
Feb. 18, 2162 20,489,077 18.042
April 9, 2166 17,061,626 22.722
Feb. 21, 2169 25,737,736 16.901
April 6, 2173 27,145,837 25.346
April 6, 2185 22,944,008 16.943
Feb. 19, 2188 23,754,564 22.906
April 9, 2192 15,588,662 18.148
Feb. 18, 2195 18,422,304 20.453
April 10, 2199 11,153,438 19.960

Images and Observations

1999 FK21's orbit is determined by observations dating back to March 26, 1971. It was last officially observed on April 26, 2018. The IAU Minor Planet Center records 1,166 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 1999 FK21:

References

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Orbital Elements

  • Epoch: 2455909.5 JD
  • Semi-major axis: 0.738751891176 AU
  • Eccentricity: 0.703125907102
  • Inclination: 12.6015368014°
  • Longitude of Ascending Node: 180.531690844°
  • Argument of Periapsis: 172.337969848°
  • Mean Anomaly: 276.482680885°

Physical Characteristics

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

Derived Characteristics

  • Orbit Period: 232 days (0.63 years)
  • Avg. Orbit Speed: 34.65 km/s
  • Aphelion Distance: 1.26 AU
  • Perihelion Distance: 0.22 AU
  • Rotation Period: 68.44 days
  • Approx. Composition: magnesium silicate and iron silicate.

Size Comparison

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.