Key Facts

  • Categorized as a Aten-class Asteroid
  • Comparable in size to a school bus or smaller
  • Will pass within 4,065,447 km of Earth in 2021
  • Classified as a Near Earth Asteroid (NEA)
  • Not a Potentially Hazardous Object
  • See orbit simulation

Overview

1998 SD9 is a very small asteroid whose orbit could bring it in close proximity to Earth. NASA JPL has classified 1998 SD9 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.

1998 SD9 orbits the sun every 215 days (0.59 years), coming as close as 0.35 AU and reaching as far as 1.06 AU from the sun. Based on its brightness and the way it reflects light, 1998 SD9 is probably between 0.038 to 0.086 kilometers in diameter, making it a small to average asteroid, very roughly comparable in size to a school bus or smaller.

Close Approaches

1998 SD9's orbit is 0.01 AU from Earth's orbit at its closest point. This means that its orbit is relatively close to Earth's orbit.

1998 SD9 has 38 close approaches predicted in the coming decades:

Date Distance from Earth (km) Velocity (km/s)
Oct. 6, 2021 4,065,447 10.817
Aug. 25, 2028 8,989,344 12.470
Oct. 1, 2031 4,996,352 9.754
Aug. 26, 2038 21,195,978 15.296
Sept. 15, 2041 7,827,052 9.318
Oct. 9, 2044 20,039,635 14.788
Aug. 31, 2051 2,012,696 10.259
Oct. 8, 2054 6,841,238 11.598
Aug. 27, 2061 4,003,720 11.344
Oct. 4, 2064 3,697,874 10.350
Aug. 26, 2071 14,633,664 13.789
Sept. 24, 2074 7,332,150 9.403
Oct. 8, 2077 27,086,792 16.461
Sept. 5, 2084 5,474,648 9.635
Oct. 10, 2087 11,375,417 12.711
Aug. 27, 2094 4,721,398 11.523
Oct. 2, 2097 4,949,531 9.854
Aug. 27, 2104 28,185,961 16.971
Sept. 6, 2107 5,064,813 9.687
Oct. 10, 2110 8,022,667 11.911
Aug. 27, 2117 11,038,785 12.978
Sept. 26, 2120 7,092,124 9.450
Oct. 10, 2123 27,032,596 16.450
Sept. 4, 2130 4,280,879 9.825
Oct. 10, 2133 9,149,984 12.152
Aug. 28, 2140 3,073,657 11.168
Oct. 6, 2143 4,011,426 10.253
Aug. 27, 2150 19,264,784 14.880
Sept. 18, 2153 8,003,827 9.332
Oct. 10, 2156 19,840,860 14.742
Sept. 1, 2163 1,381,348 10.365
Oct. 10, 2166 8,319,473 11.921
Aug. 31, 2173 1,142,825 10.402
Oct. 10, 2176 13,512,577 13.187
Aug. 28, 2180 29,898,169 17.371
Sept. 19, 2183 7,777,988 9.360
Aug. 27, 2190 11,557,521 13.088
Oct. 5, 2193 4,180,324 10.280

Images and Observations

1998 SD9's orbit is determined by observations dating back to Sept. 18, 1998. It was last officially observed on Sept. 4, 2018. The IAU Minor Planet Center records 146 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 1998 SD9:

References

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Orbital Elements

  • Epoch: 2458373.5 JD
  • Semi-major axis: 0.7029 AU
  • Eccentricity: 0.5041
  • Inclination: 3.03°
  • Longitude of Ascending Node: 166.33°
  • Argument of Periapsis: 7.06°
  • Mean Anomaly: 157.41°

Physical Characteristics

  • Diameter: ~0.050 km
  • Magnitude: 24.2

Derived Characteristics

  • Orbit Period: 215 days (0.59 years)
  • Avg. Orbit Speed: 35.57 km/s
  • Aphelion Distance: 1.06 AU
  • Perihelion Distance: 0.35 AU

Size Comparison

Orbit Simulation

Sky Map

The position of 1998 SD9 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.